Collectible Card Game Headquarters

Has been happening to me for the last few hours. I play a spell, get prompted to pay for it, tap the lands for it, and nothing. Even tapping a pain land to select the proper color mana will take away life but not apply the mana to the spell cost. Ive been playing all day fine and then it happened in the middle of one my games. Since then every game I try and create or join does the same thing. I am up to date on the software and tried exiting, rebooting, etc.

You probably only deactived the automatically payment of mana in the battlefield context menu.
To verify, if deactivated you should be abel to pay the mana by clicking on the mana symbols in the user info area.

How do I re-enable it?

Seems straight forward.