In that case,
What do you see for port 8211 traffic in the MC's data path session table?
Show datapath session table [ip of ap] | include [ip of MM]
It could be many things. For example, you have mentioned you have two IAPs, IAP should be converted to a CAP first.
Did the IAPs successfully convert to a campus AP in the first place?
Is the AP able to receive an IP address?
Is the PAPI and GRE traffic being seen in the datapath session table?
What do you see in the show datapath session table?