SIP port being remapped to random port number - External phones wont register

I have 2 external handsets. Suddenly the port numbers are being remapped from 5060 to 57529 and 57530.

Both handsets are not unreachable since this started happening.
Yesterday they were both registering on 5060 and working perfectly.

Could any suggest how or why this is happening, and where I can make changes to these port numbers so they can register back on 5060.

Much appreciated.

2 posts were merged into an existing topic: Remote handsets suddenly cant connect