Unable to send or receive iMessages on county-issued iPhones between users

Problem:County employees were unable to send or receive iMessages on their county-issued iPhones. Messages would be received on other devices but not on their phones. Multiple employees were experiencing this issue.

Solution:Have the user sign out of their Apple ID on the affected iPhone. Then have them reboot the phone before signing back into their Apple ID. This resolved the iMessage activation issue and allowed messages to be received properly on the iPhone again.