Voipbuster, SIP and codecs. hardphone or soft

I had been having trouble connecting to Voipbuster from various sources, especially my Grandstream 486.

After new problems today with Phoner softphone I realized that the issue was with codecs. It seems Voipbuster gives a not very helpful '403 forbidden' when a call nearly makes it but codecs don't match up.

Setting my Grandstream to use just G711u and G711a seems to have sorted things out. (details http://www.voipuser.org/index.php?name= ... ghlight=(.

I suspect that limiting your codecs will help connection to Voipbuster with other phones , hard and soft.

Greetings
Stephen