Pushback sequence unreliable.

Hello,

It occurs frequently that the initial communication from the cockpit (‘Ground, we are ready for pushback’), is not being answered. In most cases releasing the parking brake makes the process running again, but occasionally that doesn’t help. In such a situation pressing Shift-P has no effect. Slewing is the only option to get the aircraft moving out of its parking position. As far as I can see there is nothing wrong with the script. I’m curious whether anyone else has encountered this, and possibly has found a solution or work around. Thanks.

René