The error indicates that TLS 1.2 started to be enforced on the SQL server, and the SEPM does not have utilities that are compatible.
The SQL ODBC driver, command line utilities, and/or native client will need to be upgraded to one that supports TLS 1.2.
See Microst's documentation here:
https://support.microsoft.com/en-us/help/3135244/kb3135244-tls-1-2-support-for-microsoft-sql-server
SEPM's requirements and download instructions are found in KB article 178648