Test connection error:
Unable to establish a valid connection to the target system. Result returned the following error: [I/O Error: Read timed out]
Message: Caught an exception while collecting: Result returned the following error:[I/O Error: Read timed out ] for query: [ select top 1 name AS host from sys.servers order by server_id ]
If you are seeing the above errors the most common fix is to go into the Adapter Configuration> Advanced Configuration and change SSL from Verify or No Verify to No SSL to allow it to connect.
To check which SSL configuration is right for you, log into the SQL Server box and open SQL Server Configuration Manager.
In the left pane expand SQL Server Network Configuration and right click on Protocols for [yourServerInstance] and click properties. Check if forced encryption is set to Yes or No. If No, then No SSL would be the correct SSL setting for the adapter configuration. If Yes, then Verify (SSL enabled/certificate is verified) or No Verify (SSL enabled/certificate not verified) would be the correct SSL setting for the adapter configuration.
If that does not resolve the issue an additional check in SQL Server Configuration Manager
would be to click on the Protocols for [yourServerInstance] and in the right-hand pane, make sure that TCP/IP is Enabled.
Lastly you can right click on TCP/IP and select Properties. Select the IP Addresses tab. Here you will want to make sure that IPV4 and/or IPALL are set to the correct port that you are using. The Default Instance Port is 1433 (TCP).
If you have performed these steps and still have the same error please reach out and open a support ticket. In the ticket please include screenshots of the above steps taken.