Music on hold is not heard ,outbound calls,till 2nd try

Greetings,
I’m using Asterisk 1.8.7.1 on Ubuntu server x64.
When I’m dialing out with any of my phones, and place the other side on hold, here is what I get :
– Started music on hold, class ‘default’, on SIP/Vitel-OUT-0000001b
– Locally bridging SIP/Polycom-0000001a and SIP/Vitel-OUT-0000001b
The problem is that the other side gets silence instead of getting MOH. When brought back from hold an placed back in hold, then here is what I get :
– Started music on hold, class ‘default’, on SIP/Vitel-OUT-0000001b
and then the MOH can be heard by the other side. I’ve tested this repeatedly and was able to re-produce this behavior each time.

The issue does not occur when someone is calling inside to my system.
if any further .conf files info is needed, tell me so, I don’t want to over paste info.

Thank you .