If you updated the game, you can only play on servers that updated the game as well.
Some surf servers won't show up until a map change, and if the time was extended, you have only 3 options.

This might take a while but if you want to play with other people because you have no friends to play with, this might be the best way.

You can simply create a surf server to play alone, with friends or for others to join. All you got to do is click "Create Server" on the title screen. Then a tab will appear giving you the option to select the map you want (Usually, the suf maps have a name like this: "kz_surf_utopia"), set up the player limit (If you'd like to play alone, check the box that says "LAN") and give a name to your server. Once you enter the server, hit ESC on your keyboard and type in: sv_surf 1. That will activate surf mode (That's how you can surf!).

It's almost the same thing as the first one but, maybe the map will change into surf.

Thanks for reading!