Conference bridge not available

[a_nair]

Dear Friends,
I have an issue at one customer place for six party conference.The problem will explain below.Kindly provide me solution to close this issue.

Customer having OXO with cpu 3m at one branch ,here I loaaded the 6 party meet me conference license .Here 6 party conference is working fine for the internal users.
Another branch in another region with power cpu migrated from cpu 2.Connected these branches through VOIP by SIP trunking.
I am able to make extension to extension calls between these branches.
I set up 6 party conference master at the first branch having meet me conf license.Its working fine inside the branch.
But participants from second branch cant able to join the bridge.When they dial for join meet me prefix they get a message that conference bridge not available.


Also advise me how to activate and join meet me conference for six parties in OXO using VOIP - SIP trunking.

Regards
a_nair