Unsubscribe users

Guys, help!!
Recently we updated ur openfire server from a Win XP to a CentOs 7 Linux.
Did we migrated all user data with export and we set the same hostname and IP, so we didn’t had to remake all users configs.
The problem: some users recently related that some messages they receive don’t came up… Just appears “unsubscribe” from the sender.
What can I do about it?
Client: PSI 0.14
Server: Openfire 4.6.4

@guus Could u help me, please?