Hello,
since this problem did come up more often lately, this is a problem with an outdated Microsoft SQL Server instance and KNIME using a newer Java version which by default does not support TLS 1.0 and 1.1 anymore due to security concerns. For details see: [JDK-8256490] Release Note: Disable TLS 1.0 and 1.1 - Java Bug System
However you can re-enable it, at your own risk, by re-enable the versions by removing “TLSv1” and/or “TLSv1.1” from the jdk.tls.disabledAlgorithms security property in the java.security configuration file. You can find the file in the <KNIME_FOLDER>/plugins/org.knime.binary.jre.win32.x86_64_<VERSION>/jre/conf/security folder.
Bye
Tobias