Forbidden calls

It sounds like a classic SIP 403 error!--tgqphd|[]-->. Basically, the network server sees the first request and says "No," usually because of a split-second timing issue or a hiccup in verifying your credentials.!--tgqphd|[]-->

When you redial, it forces the system to try again, and by then, the "handshake" between your phone and the provider usually syncs up correctly. It’s like a door that’s stuck the first time you turn the handle, but opens perfectly on the second try.!--tgqphd|[]-->

If it keeps happening, it’s almost always a server-side routing glitch!--tgqphd|[]--> with the carrier or the office phone system, not the phone itself.!--tgqphd|[]-->