it seems that the server is not responding or at least that your Analytics Platform does not receive a response. Have you retried it after waiting for a while? One possibility could be that connection problems existed at that time.
Another possibility could be that KNIME is blocked by your firewall. Please check the manual of your firewall to check, if this is the case.
Furthermore, have you also to install an extension on another KNIME installation on the same computer, i.e. re-installed KNIME or re-extracted the zip-file into a new path?
If this doesn’t help there is also the possibility to download the extension manually as described here:
There seems to be a general problem.
Have you already tried to re-install KNIME on your Windows 10 machine? It could be that some files got corrupted.
Does the server you are accessing via the Microsoft SQL Server Connector run on your local machine or is it accessed via the internet?