Can someone help me with the Multiplayer Achievment?

It is with great pleasure that I inform you how much I love your game! I bought it a few years ago, and now I’m aiming to get platinum on my favorite Steam games. Given how long the game has been out, I feel that the multiplayer lobbies are mostly empty now, or at least it’s hard to form rooms and farm those famous achievements like 900,000 zombies and 1,000 automated towers in single player mode. I’ve read here on the Steam forum that years ago you considered reducing these achievements for this ver...

The game doesn't open for me, I press play and it says running and then it closes by itself, it doesn't start and I don't know what to do :c I have windows 11 and I don't know if that's why help please

As the title says. When I search for a server none come up.

.NET Runtime Error - System - Provider [ Name] .NET Runtime - EventID 1026 [ Qualifiers] 0 Level 2 Task 0 Keywords 0x80000000000000 - TimeCreated [ SystemTime] 2014-07-09T19:46:11.000000000Z EventRe...