A transport-level error has occurred when receiving results from the server. (provider: TCP Provider, error: 0 - The semaphore timeout period has expired.)

Question

Hi,

We are using SQL Server for many web application. From 31/07/2023 we are getting many sites throwing timeout or connection errors with database operations. Everything I have read online says this is likely a connection issue. How could we check to confirm such things, or are there other possible causes?

Thanks,

Anthony

Answer 1

Have you checked the SQL Server errorlog for accompanying error messages?

My prime guess, though, would be that this is a issue in your network.

Answer 2

Hi @Anthony Morriss,

"The semaphore timeout period has expired" is a Network error.

There is apparently some sort of network problem between the application and the SQL Server.

Check your Windows system event log and SQL Server errorlog to narrow down the issue.

Regards，

Zoe Hui

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Answer 3

Hi @Anthony Morriss

These kinds of errors are a client-side issue and not a Gateway-side or SQL-side issue. You may need to Check firewall settings.  Most likely you have a firewall allowing TCP connections but preventing data to flow to destination.

If you are using Firewall, make sure you configure it to allow SQL Server access as explained in below document

Configure the Windows Firewall to allow SQL Server access - SQL Server | Microsoft Learn

Thank you!