CKAN "apply changes" not working?

[Grand Ship Builder]

Hello everyone! 

 

I have a problem which whenever I check a mod, the "apply changes" button is still greyed out. I tried restarting it, reinstalling, restarting, and deleting cache, yet nothing works.

 

Does anyone have help on this problem?

 

EDIT: Fixed, realized I downgraded KSP, so I updated it again. Now works fine.  Another thing was wrong. Steam fixed it again.

Edited August 23, 2017 by Grand Ship Builder
Fixed.

[DrLicor]

Maybe you are trying a mod thats not compatible with a mod you've already installed?

On the sort button, click on installed mods, and see is some mod is marked red when the mod you want to install is checked.