ATA box is sending a signal every 9th minute

My ATA box, an i3 (Tilgin) Vood VRG322i is sending a short signal every 9th minute, and also every time I do an update of my settings in PBXes. This problem only occurs when I connect the box to PBXes and not direct to any other SIP-provider. I can connect my Siemens WLAN phone without any problem, it works perfect also with to the same extension.

I have tried to reset my hardware and also used different extensions but this small but very annoying problem continuous. I’m an inexperienced user and running out of any good ideas of solving this problem, I really hope you can help me. Searching internet I found some people using the same box having similar problem with Asterix. They solved it by removing something like "mailbox:3333", but unfortunately I can’t se how it can help me…