Group chat issue

There are three users (A,B,C) . Where A creates group and invites B and C . There B and C accept invitations .

There are total three members in room. All are chating in group. But in middle C are going offine .That time A and B countinuesly chat .After some times C comes online and rejoins group.

There is an issue that when C comes online C gets last message of group in every 5 minuts.** Why this is happening ?**

Where group name is testing.

A send message in group : 1234567890

C2S - SENT (338454169): 12345678901234567890

openfire send the message in cron job and may be you have to manage this on backend

you have to track message status .