Lately, well for the last few months, we have been experiencing a strange problem. 3 out of every 5 calls we make the person answering the call cannot hear us but we can hear them answering. If we hang up and redial immediately the call gets answered successfully and the person can hear us.
This seems to happen for all destinations we are calling. Any ideas why this is happening? I can't see anything obvious in the logs. Could it be problems with the codecs? We are using G726 ulaw.