Cannot deposit checks using mobile app

The KeyBank app is working, but the 'deposit' function for checks is completely missing. There is a separate "deposit checks" in the Pay&Transfer tab, but that also results in the following error message:
   "We Can't Process Checks Right Now. Our deposit system isn't working. There's no need to contact us - please try back later."

There's no need to contact us?!? Uhh, actually, there is, because I want to deposit some checks...