How can I use Discord's push-to-talk function when playing Star Wars: The Old Republic?

I'm attempting to use Space bar to use the microphone on discord while playing SWTOR operation groups, but it's not working. Is this simply a configuration issue? How can I solve this?

I have one screen only.

Some games run in administrator mode by default (to allow updates, for example). I don't know if SW:TOR is one of them, but if it is, Discord will be unable to read keys while the game is focused, which effectively disables its push-to-talk feature.

The fix is to run Discord in administrator mode as well. Even if the game in question is not an admin mode game, setting Discord to run with elevated permissions usually fixes problems with PTT not working correctly.

See Discord's official support page for info on how to run Discord in administrator mode.