Trying to check my wife in for her return flight today - ATL-DEN-SLC, and I get this message:

"There was a problem processing your request.We are unable to complete your check-in due to technical difficulties.Please proceed to the airport for check-in."

This comes up after I put in the reservation code, decline stretch seating and indicate she's not checking any bags.

Is this an actual technical problem, or is it a "security" issue and they're requiring her to check-in in person? And if it's the former, do you think I'll be able to check her in later today (she departs at 7:00)?