RMM Server restore PostgresDB failed from the version older than 3.3.21
From ESS-WIKI
RMM Server moved the SSL certificate file for security issue after RMM Server version 3.3.21. If the user enables SSL and tries to restore to version newer then 3.3.22 will cause the tomcat server cannot find the SSL file.
The workaround is to copy the files in "\Advantech\RMM 3.3 Server\WebApp\WEB-INF\classes\resources\*" to "\Advantech\RMM 3.3 Server\WebApp\" for each time you want to restore the Postgres DB and then restart the tomcat server.