Understanding Modem Error Codes: M01, M02, M03, M05

Nayax device showing M01, M02, M03, or M05? All modem error codes mean no internet connectivity. Identify your code, hardware fault or network issue, and follow the step-by-step guide to restore connection.

General

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Nayax U โ€บ Troubleshooting โ€บ Communication โ€บ Understanding Modem Error Codes

Understanding Modem Error Codes: M01, M02, M03 & M05

Nayax device showing a modem error, a countdown screen, or frozen on the Nayax logo? All M0x-range codes mean the device has no internet connectivity. Identify your code - hardware fault or network issue - and go straight to the fix instead of guessing at cables.

Operators
Nayax Core ยท VPOST ยท Onyx
Category: Communication
A machine on a delivery route goes dark overnight - no DEX report comes in, no sales sync, and by morning, the operator has no idea whether it sold anything or just went offline. The screen shows Cash Only or Cashless Out of Order alongside a modem code, and every one of those codes - M01, M03/M00, M05, M02/M06 - means the same root problem: no internet connectivity. But they don't share the same fix. Reseating a SIM card won't help if the real issue is a dead carrier signal at that location, and swapping SIMs won't help if the antenna cable is loose. The code on screen tells you which one you're dealing with.
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Not sure which error code you have? Check the device screen - the code appears alongside the Cash Only or Cashless Out of Order message. A countdown screen most often indicates M02 or M06.
Prerequisites

Before You Start

  • You've checked the device screen and noted the error code or symptom showing (M01, M03/M00, M05, or a countdown screen).
  • You have access to Nayax Core Management Suite, or can reach the device directly (VPOST / Onyx, Technician Mode).
  • You know whether this is a hardware fault (M01, M03/M00, M05) or a network fault (M02/M06) - see the callout below if not.
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Hardware vs. network: M01, M03/M00, and M05 are hardware faults - the fix involves physical checks on the device itself (SIM card, antenna, restart). M02/M06 is a network fault - the hardware is functional, but the SIM carrier has no signal at the location. If you're seeing a countdown screen, start with the M02/M06 guide.
Diagnose

Identify Your Code

Expand the card that matches your device screen.

M01 ยท HARDWARE No SIM / Ethernet Detected

A machine goes offline overnight and shows 'Cash Only' or 'Cashless Out of Order' with 'M01' next to it. The modem simply can't detect a SIM card or an Ethernet connection - usually a hardware fault, not a network problem.

Most likely cause

The SIM card was jarred loose during a restock or route visit and isn't seated properly.

Less obvious, still realistic

On an Ethernet-only device, the port or cable itself has failed - reseating a SIM won't help here because there isn't one to check.

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Work through these checks in order: Reseat the SIM card > Inspect and reseat the antenna cable > Restart the device > Switch to Ethernet if cellular isn't available. Stop as soon as the error clears.
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How you'll know it's fixed: The Cash Only / Cashless Out of Order message clears and the device reconnects - confirm with a test transaction or by checking the device is online in Nayax Core.

For the full click-by-click steps, open the dedicated M01 guide. 

M03 / M00 ยท HARDWARE Frozen on the Nayax Logo Screen

A device may sit frozen on the Nayax logo after a firmware update or power event; a QR code may also appear. The modem is stuck during initialization and never finishes booting.

Most likely cause

The modem got stuck mid-initialization after a restart or power interruption.

Less obvious, still realistic

A factory reset was performed via Technician Mode, but the device configuration was never reloaded from Nayax Core afterward; the device remains non-functional until it is.

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Work through these checks in order: Reseat the SIM card > Inspect and reseat the antenna cable > Restart the device > Switch to Ethernet if cellular isn't available. Stop as soon as the error clears.
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Reload configuration after a factory reset. If you restart the device via a full factory reset from Technician Mode, you must reload the device configuration from Nayax Core afterward; otherwise, the device won't operate correctly. A remote Restart Device action from Nayax Core does not require this.
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How you'll know it's fixed: The logo screen clears to the device's normal idle or Welcome Message display.

For the full click-by-click steps, open the dedicated M03/M00 guide. 

M05 ยท HARDWARE Modem Fault

A machine intermittently displays 'Cash Only' or 'Cashless Out of Order,' with M05 displayed alongside. A failure occurred during the communication process with the modem itself - a communication-layer hardware fault, distinct from a simple loose connection.

Most likely cause

A loose SIM card or an antenna cable can interrupt communication with the modem.

Less obvious, still realistic

M05 keeps returning even after the SIM, antenna, and restart checks all come back clean - this points to an internal modem fault that self-service steps can't resolve, and the device likely needs escalation.

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Work through these checks in order: Reseat the SIM card > inspect and reseat the antenna cable > restart the device. Note: unlike M01 and M03/M00, there's no Ethernet fallback step for M05 - the fault is with the modem's communication layer itself, not with which connection type it's using.
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How you'll know it's fixed: The Cash Only / Cashless Out of Order message clears and stays clear. If M05 keeps returning after all three checks, treat it as a hardware fault requiring escalation rather than repeating the checks.

For the full click-by-click steps, open the dedicated M05 guide. 

M02 / M06 ยท NETWORK Countdown Screen

A device at a remote site sits on a countdown screen, unable to connect. Unlike M01 or M05, this isn't a hardware fault - the device itself is fine. It simply can't reach the cellular network or Ethernet, most often because the SIM carrier has no signal at that location.

Most likely cause

The SIM card is inactive, expired, or on a carrier plan with no coverage at the site.

Less obvious, still realistic

The SIM itself is perfectly active, but the machine is at a genuinely low-coverage location (rural site, basement, thick concrete) - no amount of SIM replacement fixes that; Ethernet fallback is the actual answer.

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Work through these steps in order: Replace the SIM card with an active card on a compatible carrier > if no replacement SIM is available or coverage is the issue, switch to Ethernet via Nayax Core.
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How you'll know it's fixed: The countdown screen clears, and the device shows as connected in Nayax Core.

For the full click-by-click steps, open the dedicated M02/M06 guide. 

Retrieval Aid

Quick Reference: All Modem Error Codes at a Glance

Code Type What it means Symptom on screen First fix to try
M01 Hardware Modem cannot detect a SIM card or an Ethernet connection Cash Only / Cashless Out of Order Reseat the SIM card
M03 / M00 Hardware Modem stuck during initialization - device frozen on Nayax logo Frozen screen / QR code may appear Reseat the SIM card
M05 Hardware Failure during the communication process with the modem Cash Only / Cashless Out of Order Reseat the SIM card
M02 / M06 Network Cannot connect to the cellular network or Ethernet - SIM carrier unreachable Countdown screen / Cashless Out of Order Replace the SIM card
Expectation Setting

What Each Dedicated Guide Covers

  1.  
    What the error code means - a plain-language explanation of what's happening inside the device: hardware fault vs. network-layer issue, so you understand the problem before you start.
  2.  
    Ordered troubleshooting steps - numbered checks to work through in sequence, each with a YES/NO branch: if the error clears after a step, you stop; if not, you move to the next check.
  3.  
    Platform instructions where needed - steps that require software access cover both Nayax Core Management Suite (desktop) and the VPOST/Onyx device, with a video guide where applicable.
  4.  
    Clear escalation path - if all self-service steps are completed and the error persists, the guide tells you exactly what to have ready before contacting Nayax Support.
Help

Troubleshooting

What do modem error codes M01, M02, M03, and M05 mean on a Nayax device?
All M0x-range codes mean the Nayax device has no internet connectivity.
The specific code identifies the cause:
M01 means no SIM card or Ethernet is detected;
M03/M00 means the device is frozen on the Nayax logo with the modem stuck during initialization;
M05 means a failure occurred during the modem communication process;
M02/M06 indicates that the device cannot connect to the cellular network or Ethernet and displays a countdown screen.
What is the difference between a hardware modem error and a network modem error?
M01, M03/M00, and M05 are hardware faults - the issue is with the physical components of the device itself, such as the SIM card seating, antenna connection, or modem initialization. M02/M06 is a network-layer fault - the device hardware is functional, but the SIM carrier has no signal at the location, or no Ethernet connection can be established. The fix for each is different: hardware faults start with physical checks, network faults start with SIM replacement.
How do I fix a Nayax device frozen on the Nayax logo screen?
A device frozen on the Nayax logo is typically M03 or M00 - the modem is stuck during initialization. Work through four checks in order: reseat the SIM card, inspect and reseat the antenna cable, restart the device via Nayax Core or Technician Mode, and switch to Ethernet if cellular connectivity is unavailable at the location. After any factory reset, you must reload the device configuration from Nayax Core.
Why is my Nayax device showing a countdown screen?
A countdown screen most commonly indicates M02 or M06: the device cannot connect to the cellular network or to Ethernet. This is a network-layer issue, not a hardware fault. The SIM card may be inactive, expired, or on a carrier with no coverage at the location. Start by replacing the SIM card with an active card on a compatible carrier. If no replacement SIM is available, switch to Ethernet as an interim solution.
What should I check first when my Nayax device shows M01?
Start with the SIM card - a loose or unseated SIM is the most common cause of M01. Locate the SIM slot on the back of the device, pull down the silver bar to release the SIM frame, remove and inspect the card, then reinsert it firmly and push the silver bar back up to lock it in place. If M01 persists after reseating the SIM, move to the antenna cable check, then device restart, then Ethernet fallback.
Do I need to reload the configuration after restarting a device to fix a modem error?
Yes, if you perform a factory reset from the device itself via Technician Mode. A factory reset removes all device settings, and the device will not operate correctly until the configuration is reloaded from Nayax Core Management Suite. If you restart the device remotely via Nayax Core using the Restart Device action rather than a full factory reset, a configuration reload is not required.
Escalation

Still Need Help After Troubleshooting?

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If you've worked through the guide for your error code and the device is still offline, contact Nayax Support. Have your device serial number, error code, and the steps you've already completed ready to share.

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