I have some trouble with configurating my SPA504G. Each time I try to configure it, it gives me the warning "failed - authenticate". I thinks it's strange because I have another cisco ip phone with the same configuration and that phone works perfect....

I have a problem with my spa504g phone. I configured it 2 months ago and it worked perfectly. But since a week ago, if someone calls we can't hear the caller but the caller can hear us. If we call the caller back everything works back perfectly... ha...