Calls (Video or Audio) Delay

I need you support please, as I have a domain which is

OpenFire.headq.local and
domain controller running on ip: with bios name WP-WS-OFDC … and
openfire server running on ip: with bios name WP-WS-OF
and connectivity between openfire server and domain with LDAP and everything works just fine. Users can login and authenticate with Jitsi client massenger with their usernames and passwords as;
and replacing server name with the openfire server ip on jitsi advanced settings.
OpenFire Server is Version 4.0.1 and runs on host machine runs on win7 64x

So coming to the issue as users login to their Jitsi messenger and initiate a video or audio call it would initiate immediately at their end but it takes about 5 minutes to show up on the receiver end however they are on the same network so please help if any DNS records has to be added or zones to be configured ???

i have the same problem, it takes almost a minute to make the call.

How can I solve it?