Hey Slayer1920!
There are many reasons why you're having trouble with starting your server and one of those is that there are too many servers online at a time. Another issue players often encounter is the error message "cannot connect to fallback server" which can be resolved if you wait 5 minutes and try joining. If this doesn't work, there might be an issue internally with your server.
You may refer to this link for more help.
If you still are unable to start your server, may create Support ticket and our team will assist you!
Thank you!