Why Am I Seeing Login Errors of Code: T_514 When I Use a Web Browser for Resource O&M?

Symptoms

When a user attempts to log in to a resource using a web browser, the login page fails to load. A login error (Code T_514) is reported, indicating that the session is disconnected because the server does not respond for a long time and the user needs to check network and try again.

Possible Causes

• The network connection between the CBH system and the managed host is unstable.
• The network between the CBH system and the managed host is blocked.
• The managed host does not respond, leading to network disconnection.

Mind Map for Troubleshooting

Refer to the following map to locate the causes and fix the Code T_514 login error you encountered.

Figure 1 Mind map for troubleshooting

Check the Network Connection

Log in to the CBH system, ping the managed host, and check whether the network connection is normal.

• If the network connection is normal, the login failure may be caused by unstable connections.

  Restart the corresponding managed host. If the network recovers after the host is restarted, no further action is required. If the fault persists after the host is restarted, check by referring to ECS Failures or Slow ECS Responses.

• If the network connection is abnormal, the network between the CBH system and the managed host is restricted. Perform the following operations to rectify the fault:
  1. Check whether the current user is an intranet user and whether the user's access permission is restricted.

     For example, intranet users cannot access public network resources. They need to apply for the Internet access permission or WebSocket permission to access managed hosts.

  2. Check the CBH System Configuration
  3. Check the Host Resource Configuration

Check the CBH System Configuration

1. Log in to the CBH system and check whether the IP address and port number of the managed resource are correct.
2. Check whether IP address restriction is configured in the access control policy associated with the resource. Modify an ACL Rule to remove the restriction on the source IP address of the user.
3. Check the security group associated with the CBH instance and check whether the port configuration of the security group is correct. You are advised to configure a security group for a CBH instance based on the recommended CBH ports.

   If you log in to the managed host using a web browser, manually add an inbound rule that allows unrestricted access to TCP port 443 in the CBH instance security group.

4. Check whether the network ACL associated with the CBH instance on the intranet is correctly configured.

   Remove the access restriction on the IP address of the CBH instance and add the resource IP address to the destination address to allow the CBH instance to access resources.

5. After the reconfiguration, log in to the managed host again through the CBH system.

Check the Host Resource Configuration

1. Log in to the management console of the managed host as the administrator.
2. Check whether the host resource and the CBH instance are in the same VPC and region. The CBH instance can only directly access resources in the same VPC and region.
3. Check whether the security group rules associated with the managed host are properly configured.

   Remove the access restriction on the IP address of the CBH. Add the IP address of the CBH to the source address to allow CBH to access resources.

4. After the reconfiguration, log in to the managed host again through the CBH system.

Check the Host Security Hardening Measures

1. Log in to the managed host as an administrator.
2. Check the login method and login security hardening measures of the managed host by referring to the following content:
   • Enhancing Security for SSH Logins to Linux ECSs
   • Windows ECS Login Overview
   • Linux ECS Login Overview

3. Remove the login restriction by referring to the following content:
   • Why Cannot I Log In to My Linux ECS?
   • Why Cannot I Log In to My Windows ECS?

4. After removing the security hardening restrictions, log in to the managed host through the CBH system again.