I can't set existing channel as announcement channel.

I recently changed my server to a community channel so I could have a dedicated announcement channel, but the one channel I want to change won't let me set it as an announcement channel. It shows up on every other channel other than the one I'm trying to change! I thought it might be because I have bot timers for that channel, but I created a new announcement channel to test and they work there just fine. Somebody please help because this is incredibly frustrating!