Dedicated Server won't run. Need Help

First take a look at this thread about The Dedicated Server Launcher
Read through it and see if you can find the answers.

If you’re using steam, check - view / game servers / and try a direct connect, if the server is set up on your LAN check there.
I needed to direct connect to my server the first time, after that it showed in the game browser.

Also you may need to port forward through your router.

As for mods, check the mod page in steam workshop for the mod ID number.

Then type the number in this location on the launcher.

Add more mods by ID numbers separated by a comma and a space.

Good luck.