The maximum associations of the device are been reached. No more associations are possible.
The Application Program of a device with Mask Version 2.5 has 247 Group Objects, which means that 247 of the possible 250 associations are already reserved for the sending associations of these Group Objects. So only 3 additional receiving associations are guaranteed to succeed.
What to do?
Remove the additional receiving associations in order to be able to link more Group Addresses.