It is blocked with media or objects in the print, or the shaft is not clean.
To relieve a shuttle head jam:
Clear any media or blockage from the printer.
Press the cartridge button + and verify the cartridge returns to the maintenance station:
If the shuttle head does not move or moves slightly or slowly, and the motor sounds like it is trying to perform normal operation, contact Pitney Bowes. The set screws on the motor pulley that drives the shuttle head belt may have come loose, and this situation requires a service call.
If the cartridge returns to the maintenance station, wipe the print head shaft with a dry, soft, lint free, cotton cloth.
Remove the print head holder and clean it with a soft cloth.
Replace the print head holder and resume operation.