I cannot connect to my local SQL Server Express (2012, but the version shouldn't matter) from my server (Windows 2008 R2) to use a tool on it (APEX SQL Data Diff if you are wondering). I can browse the network servers fine, and select my local instance from the dropdown of available servers, but when I go to search tables on the server, it times out with this error message (same is true of SSMS).
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 28 - Server doesn't support strong text requested protocol) (Microsoft SQL Server, Error: -1)
I have enabled the firewall - that's not it.
I have allowed remote connections - that's not it.
SQL Server Browser service is on and passed through the firewall - that's not it.
I can connect fine with the same tools TO the server, but FROM the server it fails.
Any ideas?
Thanks to this article for getting me somewhere with the error message. The issue is the necessary network protocols are disabled by default in SQL Server Express. I had to go to Sql Server Configuration Manager locally and turn on "Named Pipes" and "TCP/IP". After that, you need to restart the SQL Server Browser and SQL Server(instance) services.
While I did not have to, you may also need to check in "SQL Server Network Configuration" under "Protocols" for settings that need adjusted there.
Hope this helps someone else!
SQL Configuration Manager:
The picture has the wrong group selected on the link panel: it should be SQL Server Network Configuration → Protocols for SQLEXPRESS.
Don't forget to also check under "SQL Server Network Configuration" -> Protocols for YourInstance. I was a bonehead and forgot to look there too.
来源：https://stackoverflow.com/questions/13238219/sql-server-express-cannot-connect-error-28-server-doesnt-support-requested-p