Unknown RTP codec 126 received from

Dear

i have issue when i tried to call vpn extension i get

Unknown RTP codec 126 received from

but they can call me and the freepbx server located inside my network

so could you help me please

and let me if you need any advanced info , log

What codecs are using and with what preference on your inbound and outbound calls ?

i just use Ulaw and alaw codecs