No video from my corespondants after reboot

Hello everybody

I just installed 4.0.1 Openfire with Ofmeet 3.9 plugin on a CENTOS 6.7
I have opened my range ports (NAT) UDP 5000/6000 and 50000/60000.

I deactivated IPtables on my machine to do a test and it worked .
I made a conf with 6 people.

after reboot the machine the video of my correspondent no longer appears : /
my iptables service is always deactivated

I see in the logs pass
INFOS: timeout for pair: -> (data.RTP), failing. .

Any idea why I can not see the video of my correspndants ?

Thanks in advance