Here is the error message from /var/log/mineos.log
[server] received request \"restart\"","timestamp":"2018-05-21T04:00:00.342Z"}
{"command":"restart","source":"0 0 */2 * *","msg":"","enabled":true,"success":false,"err":"up","time_resolved":1526875200351,"level":"error","message":"[server] command \"restart\" errored out:","timestamp":"2018-05-21T04:00:00.351Z"}
{"level":"info","message":"[server2] received request \"restart\"","timestamp":"2018-05-21T04:00:00.559Z"}
{"command":"restart","source":"0 0 */2 * *","msg":"","enabled":true,"success":false,"err":"Cannot start server without a designated jar/phar.","time_resolved":1526875201736,"level":"error","message":"[server2] command \"restart\" errored out:","timestamp":"2018-05-21T04:00:01.736Z"}
It seems as though the error was as expected when there is no specified jar. So I checked server.config and sure enough it wasn’t there. The mc account has read and write access as well as some execute access to the /var/games/minecraft subdirectories. The mc account is owner on everything within it as well. I created the server with the mc account too. Since each time I tried specifying a jar for my server within the webui I used the mc account to manually edit the server.config file.