Handling the “No serial number returned” Error

Handling the “No serial number returned” Error

If you see the error “No serial number returned” in NX, it means the POS system cannot communicate with the IDTech VP3350 payment device. This issue originates from the VP3350 itself when it loses connection with the POS device.

Why This Happens

The VP3350 sometimes loses its active connection to the POS device, preventing NX from retrieving the required serial number. When this occurs, NX cannot properly initialize communication with the card reader.

Recommended Steps to Resolve

1. Relaunch the NX App Close the NX App completely.
   1. Reopen the app and log in.
   2. Retry the payment process.
2. Reboot the POS Device (via Esper)
   1. If relaunching the NX App does not resolve the issue, go to your Esper management console.
   2. Select the affected POS device.
   3. Perform a remote reboot of the device.
   4. Once restarted, NX will launch and you may retry the payment process. 

Key Notes

• This error is tied specifically to the VP3350 card reader losing connection.
• It is not caused by the NX App itself.
• Following the steps above typically resolves the issue quickly.

Summary

When NX shows “No serial number returned”, it indicates a VP3350 connection issue. Start by relaunching the NX App. If that doesn’t work, reboot the POS device through Esper. After these steps, the VP3350 should reconnect properly and transactions can continue.