The ark search server function is a little bit brocken so here's a step by step guide on how to fix it!

1) In the top-left of steam press view and then servers.

2) Choose favorites.

3) Klick on add a server.

4) Enter the ip of the server.

Server list:                                                 PVP

The island: 81.82.251.116:8998
Ragnarok: 81.82.251.116:8988
Aberration: 81.82.251.116:8967 
Scorched Earth: 81.82.251.116:8978
The Center: 81.82.251.116:8056 Extinction: 81.82.251.116:8066
Hope: 81.82.251.116:8076            Valguero: 81.82.251.116:8526

List:

Server list:                                                  PVE

The island: 81.82.251.116:9889    Ragnarok: 81.82.251.116:6988
Aberration: 81.82.251.116:6967 
Scorched Earth: 81.82.251.116:6978
The Center: 81.82.251.116:6056 Extinction: 81.82.251.116:6066
Valguero: 81.82.251.116:6526

5) Press Find games at this address.

6)Press add selected game server to favorites.