Is visual studio throwing the error " Server targets are not currently supported from this engine distribution"?
Seems like the message you would get from within the editor when choosing a target from a blueprint build only
Right click on the project file => “switch unreal engine” and check that you have the source build engine from the drop-down selected.
If you have the regular build:
- delete old project folders (Intermediate,Saved, .vs, Binaries and .sln file)
- do a fresh Generate Visual Studio project files
- run visual studio and build server and client