403- Your request is forbidden?

What on earth does this mean and how do i resolve this. I have 2 asterisk servers and the one works fine and the other gives me tis error. The both are the same build(ISO ver2.1) please help me resolve this

More information is needed. What is the configuration, what is the dialplan between the two, and what does a verbose CLI say when you make the attempt?

There are two servers, lets call them server1 and server2, are linked with a IAX trunk. Sever1 is the one with the problem(witch only happen when it feels like it). When i call an extention from Server1 to Server2 I have never encountered the problem.

Sometimes when i dail out via a PSTN trunk I get the above mentioned error on the screen of the phone(Grandstream 2000). I have noticed that his also only happens if my 2nd trunk is being used. The servers are also set up to use the IAX trunk to make an external call if all the trunks on that specific server are being used.

Will have to wait for the CLI output untill this happens again