My case was different but error message was same. I fixed it w/o calling TAC. But this thread helped me to see in right direction.I noticed login issue over MRA. After running PRT through Cisco Tool, it told me various stuff but one was to check IMP ...

Never a good idea to do any system changes during business hours. I think it does impact some services. You need to get with Cisco and understand the impact. IHTH.