Unable to retrieve device when establishing device trust (LTM 15.1.2)

I am establishing a device group for config sync (not HA or failover). When establishing device trust, bigip1 is able to Retrieve Device Credentials from bigip2. However, when doing the same from bigip2 to bigip1, i get a timeout. When i run a tcpdump on each LTM i can see the traffic arriving/leaving successfully. Is there any permission/access setting i should look for?