The “No M Key” message shows on your pin pad screen & you are unable to complete transactions.

This message may also read “Pin Pad Has Lost Encryption Key.”

This may occur if the unit is connected to a power source before the pin pad being connected to the terminal. All parts & cords must be connected to each other prior to being connected to your power source (outlet). Physical damage to equipment may also cause this error.


  1. Shut down your equipment.
  2. Ensure the pin pad is plugged into POS terminal.
  3. Reconnect device to power source.
  4. Restart your equipment.

If you’re still having trouble, please submit a support request for support.

Need more help with this?
Click to request support

Was this helpful?

Yes No
You indicated this topic was not helpful to you ...
Could you please leave a comment telling us why? Thank you!
Thanks for your feedback.