Connecting to vCenter Server using the VMware vSphere Client fails with the error: An unknown connection error occured. The request failed due to an SSL Error

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:

• Connecting to vCenter Server using the VMware vSphere Client and PowerCLI fails.
  
  
• You see the error:
  
  An unknown connection error occured. (The request failed due to an SSL Error. (The request was aborted. Could not create SSL\TLS secure channel.)
  
  
• Running the openssl.exe s_client -connect hostname:443 command reports an SSL handshake error.
  
  Note: hostname is the name of vCenter Server.
  
  
• When you try InvokeMethod through the MOB you get the error:
  
  Possible XSRF (Cross-Site Request Forgery) detected

Environment

VMware vCenter Server 5.5.x
VMware vCenter Server 5.1.x
VMware vCenter Server 5.0.x

Cause

This issue occurs when vCenter Server cannot accept the SSL version used by the VMware vSphere Client (or other connecting process) and therefore rejects the connection.

Resolution

To resolve this issue, check the current set of SSL versions acceptable to vCenter Server, then if required, reset that parameter to accept all versions.

Note: As a precaution, take a backup of the vCenter Server database.

1. Connect to the vCenter Server database.
   
   
2. To check the current parameter value, run the SQL statement:
   
   select * from VPX_PARAMETER where NAME = 'SSL.Version'
   
   
3. If the parameter SSL.Version is not set to "all" (to accept all versions of SSL), run the SQL statement:
   
   update VPX_PARAMETER set VALUE = 'all' where NAME = 'SSL.Version'
   
   
4. Disconnect from the vCenter Server database.

Note: To troubleshoot the issue when the SSL.Version parameter is already set to "all", see:

• Troubleshooting network and TCP/UDP port connectivity issues on ESX/ESXi (2020669)
• Locating and troubleshooting information about using SSL certificates in VMware Products (2013423)

Additional Information

Locating and troubleshooting information about using SSL certificates in VMware Products
Troubleshooting network and TCP/UDP port connectivity issues on ESX/ESXi
VMware vSphere Client を使用して vCenter Server に接続しようとすると、次のエラーで失敗する：不明な接続エラーが発生しました。SSL エラーが発生したため、要求に失敗しました (An unknown connection error occured. The request failed due to an SSL Error)
使用 VMware vSphere Client 连接到 vCenter Server 失败并显示以下错误：发生未知连接错误。由于 SSL 错误，请求失败 (An unknown connection error occured.The request failed due to an SSL Error)