A connection error 10054 might occur post SQL Server upgrade

After a Microsoft SQL Server upgrade, you experience a connection error. The error is likely to continue even after you use the local system account for the SQL Server Agent service.

Symptoms

After you upgrade Microsoft SQL Server Standard Edition (STD), SQL Server Agent starts and stops immediately. Additionally, you receive one or more of the following error messages:

SQL Server does not accept the connection (error: 10054). Waiting for SQL Server to allow connections. Operation attempted was: Verify Connection on Start.

SQLServer Error: 10054, SSL Provider: An Existing connection was forcibly closed by the remote host. [SQLSTATE 08001]

SQLServer Error: 10054, Client unable to establish connection [SQLSTATE 08001]

Cause

Sometimes after a Microsoft SQL Server upgrade, TLS is disabled and you might experience a connection error. Check whether the TLS protocol is disabled after the upgrade is installed.

Resolution

To resolve the error, follow these steps:

1. Enable TLS by setting the following registry entries:

   Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS1.0

   Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS1.1

   Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS1.2

2. Restart the computer to make sure that the change is applied.

See also

An existing connection was forcibly closed by the remote host (OS error 10054)