Cannot create Multiplayer

Garry's Mod general
#1

Whenever I attempt to make a multi player server, it sends me back to the main menu. Is there any way I could fix this?

#2
  1. Delete garrysmod folder.
  2. Relaunch Gmod.

Failing this, reinstall.

#3

I have tried this before, didn’t work.

#4

Any help?