Serious [WW3] Can't connect due to map

[Holymilk]

When I try to join the WW3 server with the basic things I need like the map, player models, weapon models, etc. It says that the map I'm using (the one that's in the content pack) differs from the server's. Help

 

[Khiel]

When I try to join the WW3 server with the basic things I need like the map, player models, weapon models, etc. It says that the map I'm using (the one that's in the content pack) differs from the server's. Help

Uninstall it from workshop, and either:
a. delete the corresponding .gma file
or
b. do menu_cleanupgmas in gmod