- Tutorial
- Release Notes and Announcements
- Release Notes
- Public Image Release Notes
- Announcements
- Temporary Solution for the Windows Blue Screen Issue Caused by CrowdStrike Security Software on July 19, 2024
- Announcement on Flexible Discounts for Spot Instances in Some Regions
- Updating Some Image Pip Package Management Tools for CentOS 7
- CentOS 8 End of Maintenance
- Discontinuation of Support for SUSE Commercial Images
- Price Reduction in Selected Availability Zones
- OrcaTerm Proxy IP Addresses Updates
- Pay-as-you-go Price Adjustments for Standard S3 CVMs in the Silicon Valley Region
- Vulnerability repairing for Linux images
- Stopping supporting for Ubuntu 10.04 images
- Solution to Tomcat Start Failure on Ubuntu14.04
- Upgrading Virtio network card drive for Windows CVMs
- About Configuration of Security Group Port 53
- Windows Server 2003 System Images End of Support Announcement
- End of Support for Windows Server 2008 R2 Enterprise Edition SP1 64-bit System Images
- Product Introduction
- Purchase Guide
- Getting Started
- Operation Guide
- Operation Guide Overview
- Use Limits
- Convenience Features
- Instances
- Creating Instances
- Managing Instance Launch Template
- Batch Sequential Naming or Pattern String-Based Naming
- Logging In to Linux Instances
- Logging in to Windows instance
- Adjusting Configuration
- View Instance Details
- Renaming Instances
- Resetting Instance Password
- Managing Instance IPs
- Changing Security Group
- Conversion from Pay-As-You-Go to Monthly Subscription
- Searching for Instances
- Exporting Instance List
- Renewing Instances
- Starting Up Instances
- Shutting Down Instances
- Restarting Instances
- Reinstalling System
- Using Tencent Cloud Automation Tools to execute commands
- Terminating/Returning Instances
- Enabling Instance Termination Protection
- Instance Repossession or Recovering
- Spot Instances
- Querying the Repossession Status of a Spot Instance
- No Charges When Shut Down for Pay-as-You-Go Instances
- Managing Roles
- Enabling and Disabling Hyper-Threading
- Reserved Instances
- Images
- Migrating Servers
- Maintenance Tasks
- Cloud Disks
- Networking
- Security
- Security Groups
- Protection of Sensitive Operations
- Managing Login Password
- Managing SSH Keys
- Spread Placement Group
- Unblocking Port 25
- Tags
- Monitoring and Alarms
- Sample Console Configuration
- Practical Tutorial
- Best Practices
- Choosing the CVM Model
- Setting up a Website
- Building an Environment
- Building a Website
- Building an Application
- Sending Emails through Port 465
- Building a Visual GUI
- Data Backup
- Uploading Local Files to CVM
- Copying Local Files to CVMs
- Uploading Files from Windows to a Windows CVM via MSTSC
- Uploading Files from MacOS to Windows CVM Using MRD
- Uploading Files from Linux to Windows CVM using RDP
- Uploading files via WinSCP to a Linux CVM from Windows
- Uploading Files from Linux or MacOS to Linux CVM via SCP
- Uploading Files from Linux to a CVM Using FTP
- Uploading Files from Windows to a CVM Using FTP
- Other CVM Operations
- CVM Access to COS via a Private Network
- Best Practices for Boot Mode Legacy BIOS and UEFI
- Recovering Data on Linux CVMs
- Managing Disk Space on Windows CVMs
- Changing Kernel of a Linux Instance Manually
- Setting Up Windows-based AD Domain on a CVM
- Network Performance Test
- High-throughput Network Performance Test
- Using USB/IP to Share USB Devices in Linux
- Using RemoteFx to Redirect USB Devices in Windows
- Using AVX-512 Instructions to Accelerate AI Applications on CVM
- Building Tencent SGX Confidential Computing Environment
- Configuring Persistent Memory in M6p Instances
- Calling Cloud APIs via Python to Share Custom Images in Batches
- Operations Guide
- Initializing Data Disks
- Environment Configurations
- Installing Software
- User Data
- Work with Operating Systems
- System Activation
- System Updates
- System Shutdown
- Configuring High-performance Power Management
- Windows Recovery Mode
- Updating the Virtio ENI Driver
- Modifying SID
- Modifying VNC Resolution
- Ensuring Unique SIDs for CVMs Using Sysprep
- Use of the atop Monitoring Tools by Linux Instances
- Introduction to Linux Kernel Parameters
- Others
- Troubleshooting
- Instance-Related Failures
- CVM Login Failures
- Windows Instance Login Failures
- Windows Instance Login Failures
- An authentication error occurred when you tried to log in to a Windows instance remotely
- Failed to Reset the CVM Password or the CVM Password Is Invalid
- Connection to a Windows CVM through Remote Desktop was denied
- Requires network-level identity verification
- Problems occurred when you tried to log in to a Windows CVM remotely on Mac
- Failed to log in to a Windows CVM due to high CPU and memory usage
- Failed to connect to a remote computer through Remote Desktop
- Credentials Not Work
- Windows instance: no remote Desktop license server can provide license
- Remote Login Failure Due To Port Issues
- Linux Instance Login Failures
- Linux Instance Login Failures
- Unable to Log in to a Linux Instance via SSH Key
- Failing to log in to a Linux CVM due to high CPU and memory usage
- Remote Login Failure due to Port Issues
- VNC Login Error (Module is Unknown)
- VNC Login Error (Account Locked due to XXX Failed Logins)
- VNC Login Error (Login Failed with Correct Password)
- VNC or SSH Login Error (Permission Denied)
- Login Failure Due to /etc/fstab Configuration Errors
- sshd Configuration File Permissions
- Infinite Loop Call in /etc/profile
- Login Failure Due to Server Isolation
- Login Failure Due to High Bandwidth Occupation
- Remote Connect Failure Due to Security Group Settings
- Troubleshooting Linux Instance Issues via VNC and Rescue Mode
- Failed to shut down or restart a CVM
- Network Namespace Creation Failure
- Kernel and IO Issues
- Missing System bin or lib Soft Link
- Suspected Infection with Virus
- "no space left on device" Error During File Creation
- Linux CVM Memory Issues
- Network Related Failures
- Instance-Related Failures
- API Documentation
- History
- Introduction
- API Category
- Region APIs
- Instance APIs
- RunInstances
- DescribeInstances
- DescribeInstanceFamilyConfigs
- DescribeInstancesOperationLimit
- InquiryPriceRunInstances
- InquiryPriceResetInstance
- InquiryPriceResetInstancesType
- StartInstances
- RebootInstances
- StopInstances
- ResizeInstanceDisks
- ResetInstancesPassword
- ModifyInstancesAttribute
- EnterRescueMode
- ExitRescueMode
- InquirePricePurchaseReservedInstancesOffering
- InquiryPriceResizeInstanceDisks
- TerminateInstances
- ModifyInstancesProject
- ResetInstancesType
- DescribeInstancesStatus
- DescribeReservedInstancesConfigInfos
- DescribeZoneInstanceConfigInfos
- PurchaseReservedInstancesOffering
- ResetInstance
- DescribeInstanceTypeConfigs
- DescribeInstanceVncUrl
- Cloud Hosting Cluster APIs
- Image APIs
- Instance Launch Template APIs
- Making API Requests
- Placement Group APIs
- Key APIs
- Security Group APIs
- Network APIs
- Data Types
- Error Codes
- FAQs
- Related Agreement
- Glossary
- Tutorial
- Release Notes and Announcements
- Release Notes
- Public Image Release Notes
- Announcements
- Temporary Solution for the Windows Blue Screen Issue Caused by CrowdStrike Security Software on July 19, 2024
- Announcement on Flexible Discounts for Spot Instances in Some Regions
- Updating Some Image Pip Package Management Tools for CentOS 7
- CentOS 8 End of Maintenance
- Discontinuation of Support for SUSE Commercial Images
- Price Reduction in Selected Availability Zones
- OrcaTerm Proxy IP Addresses Updates
- Pay-as-you-go Price Adjustments for Standard S3 CVMs in the Silicon Valley Region
- Vulnerability repairing for Linux images
- Stopping supporting for Ubuntu 10.04 images
- Solution to Tomcat Start Failure on Ubuntu14.04
- Upgrading Virtio network card drive for Windows CVMs
- About Configuration of Security Group Port 53
- Windows Server 2003 System Images End of Support Announcement
- End of Support for Windows Server 2008 R2 Enterprise Edition SP1 64-bit System Images
- Product Introduction
- Purchase Guide
- Getting Started
- Operation Guide
- Operation Guide Overview
- Use Limits
- Convenience Features
- Instances
- Creating Instances
- Managing Instance Launch Template
- Batch Sequential Naming or Pattern String-Based Naming
- Logging In to Linux Instances
- Logging in to Windows instance
- Adjusting Configuration
- View Instance Details
- Renaming Instances
- Resetting Instance Password
- Managing Instance IPs
- Changing Security Group
- Conversion from Pay-As-You-Go to Monthly Subscription
- Searching for Instances
- Exporting Instance List
- Renewing Instances
- Starting Up Instances
- Shutting Down Instances
- Restarting Instances
- Reinstalling System
- Using Tencent Cloud Automation Tools to execute commands
- Terminating/Returning Instances
- Enabling Instance Termination Protection
- Instance Repossession or Recovering
- Spot Instances
- Querying the Repossession Status of a Spot Instance
- No Charges When Shut Down for Pay-as-You-Go Instances
- Managing Roles
- Enabling and Disabling Hyper-Threading
- Reserved Instances
- Images
- Migrating Servers
- Maintenance Tasks
- Cloud Disks
- Networking
- Security
- Security Groups
- Protection of Sensitive Operations
- Managing Login Password
- Managing SSH Keys
- Spread Placement Group
- Unblocking Port 25
- Tags
- Monitoring and Alarms
- Sample Console Configuration
- Practical Tutorial
- Best Practices
- Choosing the CVM Model
- Setting up a Website
- Building an Environment
- Building a Website
- Building an Application
- Sending Emails through Port 465
- Building a Visual GUI
- Data Backup
- Uploading Local Files to CVM
- Copying Local Files to CVMs
- Uploading Files from Windows to a Windows CVM via MSTSC
- Uploading Files from MacOS to Windows CVM Using MRD
- Uploading Files from Linux to Windows CVM using RDP
- Uploading files via WinSCP to a Linux CVM from Windows
- Uploading Files from Linux or MacOS to Linux CVM via SCP
- Uploading Files from Linux to a CVM Using FTP
- Uploading Files from Windows to a CVM Using FTP
- Other CVM Operations
- CVM Access to COS via a Private Network
- Best Practices for Boot Mode Legacy BIOS and UEFI
- Recovering Data on Linux CVMs
- Managing Disk Space on Windows CVMs
- Changing Kernel of a Linux Instance Manually
- Setting Up Windows-based AD Domain on a CVM
- Network Performance Test
- High-throughput Network Performance Test
- Using USB/IP to Share USB Devices in Linux
- Using RemoteFx to Redirect USB Devices in Windows
- Using AVX-512 Instructions to Accelerate AI Applications on CVM
- Building Tencent SGX Confidential Computing Environment
- Configuring Persistent Memory in M6p Instances
- Calling Cloud APIs via Python to Share Custom Images in Batches
- Operations Guide
- Initializing Data Disks
- Environment Configurations
- Installing Software
- User Data
- Work with Operating Systems
- System Activation
- System Updates
- System Shutdown
- Configuring High-performance Power Management
- Windows Recovery Mode
- Updating the Virtio ENI Driver
- Modifying SID
- Modifying VNC Resolution
- Ensuring Unique SIDs for CVMs Using Sysprep
- Use of the atop Monitoring Tools by Linux Instances
- Introduction to Linux Kernel Parameters
- Others
- Troubleshooting
- Instance-Related Failures
- CVM Login Failures
- Windows Instance Login Failures
- Windows Instance Login Failures
- An authentication error occurred when you tried to log in to a Windows instance remotely
- Failed to Reset the CVM Password or the CVM Password Is Invalid
- Connection to a Windows CVM through Remote Desktop was denied
- Requires network-level identity verification
- Problems occurred when you tried to log in to a Windows CVM remotely on Mac
- Failed to log in to a Windows CVM due to high CPU and memory usage
- Failed to connect to a remote computer through Remote Desktop
- Credentials Not Work
- Windows instance: no remote Desktop license server can provide license
- Remote Login Failure Due To Port Issues
- Linux Instance Login Failures
- Linux Instance Login Failures
- Unable to Log in to a Linux Instance via SSH Key
- Failing to log in to a Linux CVM due to high CPU and memory usage
- Remote Login Failure due to Port Issues
- VNC Login Error (Module is Unknown)
- VNC Login Error (Account Locked due to XXX Failed Logins)
- VNC Login Error (Login Failed with Correct Password)
- VNC or SSH Login Error (Permission Denied)
- Login Failure Due to /etc/fstab Configuration Errors
- sshd Configuration File Permissions
- Infinite Loop Call in /etc/profile
- Login Failure Due to Server Isolation
- Login Failure Due to High Bandwidth Occupation
- Remote Connect Failure Due to Security Group Settings
- Troubleshooting Linux Instance Issues via VNC and Rescue Mode
- Failed to shut down or restart a CVM
- Network Namespace Creation Failure
- Kernel and IO Issues
- Missing System bin or lib Soft Link
- Suspected Infection with Virus
- "no space left on device" Error During File Creation
- Linux CVM Memory Issues
- Network Related Failures
- Instance-Related Failures
- API Documentation
- History
- Introduction
- API Category
- Region APIs
- Instance APIs
- RunInstances
- DescribeInstances
- DescribeInstanceFamilyConfigs
- DescribeInstancesOperationLimit
- InquiryPriceRunInstances
- InquiryPriceResetInstance
- InquiryPriceResetInstancesType
- StartInstances
- RebootInstances
- StopInstances
- ResizeInstanceDisks
- ResetInstancesPassword
- ModifyInstancesAttribute
- EnterRescueMode
- ExitRescueMode
- InquirePricePurchaseReservedInstancesOffering
- InquiryPriceResizeInstanceDisks
- TerminateInstances
- ModifyInstancesProject
- ResetInstancesType
- DescribeInstancesStatus
- DescribeReservedInstancesConfigInfos
- DescribeZoneInstanceConfigInfos
- PurchaseReservedInstancesOffering
- ResetInstance
- DescribeInstanceTypeConfigs
- DescribeInstanceVncUrl
- Cloud Hosting Cluster APIs
- Image APIs
- Instance Launch Template APIs
- Making API Requests
- Placement Group APIs
- Key APIs
- Security Group APIs
- Network APIs
- Data Types
- Error Codes
- FAQs
- Related Agreement
- Glossary
This document describes how to troubleshoot instance login failures after you purchase Cloud Virtual Machine (CVM) instances, helping you locate and resolve CVM login failures.
This document describes how to determine possible causes of instance login failures after you purchase Cloud Virtual Machine (CVM) instances, helping you locate and resolve CVM login failures.
Possible Causes
The following figure shows the primary causes of CVM instance login failures and their probabilities. If you cannot connect to an instance, we recommended you use the diagnosis tool and perform troubleshooting as instructed below.
Troubleshooting
Confirming the instance type
You must first determine whether your purchased instance is a Windows system instance or Linux system instance. The causes of login failures vary by instance types. According to your purchased instance type, refer to the following documentation to locate and resolve the issue.
Using the diagnosis tool to locate the causes
Tencent Cloud provides Port Verification to help you determine possible causes of login failures. More than 70% of login issues can be checked and located by this tool.
Self-Diagnosis Tool
Problems that can be diagnosed include high bandwidth usage rate, zero public network bandwidth, high server workload, improper security group rules, DDoS attack blocking, security isolation, and account in arrears.
Port Verification Tool
This tool can diagnose security group- and port-related problems. If there is a security group configuration issue, you can use Open All Ports function of the tool to open all commonly used interfaces of the security group.
If you locate the cause of the issue using the tool, we recommend you follow the corresponding issue guidelines to resolve it.
Restarting Instance
After the diagnosis tool has located and managed the corresponding issue, or it is still not possible to locate the cause of the login failure using the diagnosis tool, you can restart the instance and connect remotely again to see whether the connection succeeds.
For information about how to restart an instance, see Restart Instance.
Other common causes of login failures
If you cannot locate the cause of the issue following the above-mentioned steps, or you receive the following error messages when logging in to the CVM, refer to the following solutions.
Windows Instances
Linux Instances
Subsequent Operations
If you still cannot log in remotely following the above-mentioned steps, save the related logs and self-diagnosis results, then Submit Ticket.
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