Problems with loading server lists, out of ideas

Ok so I’ve been having some pretty bad problems with gmod lately. After spending most of last night and all of this morning just getting to the point to where the Gamemode list would even load in under 10 minutes, I ended up port forwarding. I did include ports 27000 to 27050, which are what the game servers I play on are using.

However

I am unable to connect entirely. The best I’ve gotten was having 20 something players on 3 servers, none of which were the servers I play on. I tried to manually connect in console using connect [IP], though it said it failed after 4 retries. When I included the port at the end of the IP, it said “The server you are trying to connect to is using an older version of the game”.

Update - after 4-5 times of trying to join my friend’s game, it started to connect, but then said “the server you are trying to join is running an older version of the game”…

I have a friend that is online and playing right now. When I take my laptop to his house, I am able to play also, and his server loads up almost immediately. On my desktop at home however, that is far from the case. I hold a solid 2.1MB/s download rate, so I don’t know why I’m having so many problems. Can anyone help me out?

Here are the things I’ve tried:

Restarting Gmod
Restarting my computer
Uninstalling/reinstalling Gmod
Adding MasterServer and MasterServer2 to my config directory
Verifying file cache
opting in/out of Dev content
uninstalling/deleting all my addons
Port forwarding
powering off/on my modem countless times

Should I be using a static IP or DHCP?

Thanks for any help in advance