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Slave iPad not connecting to the Master: troubleshooting

Step-by-step checks to reconnect a Slave iPad or waiter pad to your Master in Nomni POS.

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Written by Lucien Hopkinson

Use this guide when a Slave iPad (a second POS or waiter pad) stops getting orders or tables from the Master, shows as offline, or won't appear in the Master's Server List. Work through the checks in order. Most connections come back by step 6.

Important: don't unplug, reset or restart your router or access point unless Nomni support asks you to. Orders on a Slave that can't reach the Master are kept and sent again once it reconnects. They aren't lost.

How to tell your iPads are connected

On the Master, go to Settings > Connection. Every Slave should be in the Server List with a green signal. On each Slave, the Master should be in its Server List.

1. Keep Nomni POS open and awake on the Master

  1. Look at the Master iPad. Nomni POS must be open on screen. If it's on another app, or the iPad has locked, no other iPad can connect to it.

  2. On every iPad, go to iPad Settings > Display & Brightness > Auto-Lock and choose Never.

  3. Go back into Nomni POS.

2. Put every iPad on the same Wi-Fi network

  1. On each iPad, go to iPad Settings > Wi-Fi.

  2. Check every iPad is on the same POS network (the one with Nomni POS or Abacus in its name). Use the 5G network unless we've advised otherwise. A guest network won't work.

  3. Tap the i next to the network and turn Private Wi-Fi Address off.

  4. Go to iPad Settings > Nomni POS and turn Local Network on.

3. Check the server modes

  1. On the Master, go to Settings > Connection and check Master is selected.

  2. On each other iPad, check Slave is selected.

  3. Only one iPad can be the Master. If you see the warning "Running multiple Masters on the same network may make the POS system unstable!", set the extra iPad back to Slave.

4. Check the Master's device address hasn't changed

  1. On the Master, go to Settings > Connection and look at DEVICE ADDRESS. It must show a number, for example 192.168.9.20. If it's blank, tap RESTART SERVER.

  2. Check each iPad has its own, different address on the same network (the first three groups of numbers match).

  3. On each Slave, check the Master address it's connecting to matches the Master's DEVICE ADDRESS exactly. If the Master's address has changed (for example after a router or power change), the Slave can't find it. Reconnect it in step 6.

To stop the Master's address changing again, ask your IT or network provider to give the Master iPad a fixed address (a DHCP or address reservation) on your router.

5. Make sure the network allows iPads to talk to each other

Nomni POS iPads talk to each other directly over your local network on port 8080. If your iPads are on the same network but still can't see each other, ask your IT or network provider to check that:

  • Client or AP isolation (often on by default for guest Wi-Fi) is off for the POS network.

  • Device-to-device traffic on port 8080 isn't blocked by a firewall.

6. Reconnect the Slave to the Master

  1. On the Master, go to Settings > Connection, tap the × next to every device in the Server List, then tap RESTART SERVER.

  2. On the Slave, go to Settings > Connection, tap RESTART SERVER, then tap the × next to every device in its Server List.

  3. Type the Master's DEVICE ADDRESS into the grey box on the Slave and tap Connect. Typing the address is more reliable than Auto Connect.

  4. Check the Slave now shows in the Master's Server List with a green signal. Repeat for each Slave.

Remove any duplicate entries in the Server List, especially ones on a different network address, with the ×.

7. Check every iPad is on the same app version

  1. On each iPad, go to Settings > System and check the version number.

  2. If any iPad is behind, update it from the App Store, starting with the Master. Don't delete the app on the Master, as you could lose orders. See How to update Nomni POS from the App Store.

8. Run a Master Sync if menus or settings don't match

Master Sync pulls menus and settings from Nomni Console. It doesn't reconnect a Slave to the Master, so only use it once the iPads are connected and something still looks different.

  1. On the iPad that looks wrong, go to Settings > Sync and tap MASTER SYNC.

  2. Wait for the success message. If you see Master Sync Incomplete, run it again.

Then sync any unsynced orders. See How do I sync Unsynced Orders?.

9. Restart in the right order

If it's still not connecting, restart the app in this order:

  1. Close Nomni POS on every Slave.

  2. Close and reopen Nomni POS on the Master. Wait until it's fully open and shows a DEVICE ADDRESS.

  3. Open Nomni POS on each Slave, then reconnect it as in step 6.

Still not working?

Contact us in the chat and include:

  • Your venue name.

  • Which iPad is the Master, and which Slave isn't connecting (the device names).

  • The DEVICE ADDRESS of the Master and of the Slave.

  • The Nomni POS version on each iPad.

  • Any error message (a screenshot helps) and roughly when it started.

  • Which of the steps above you've already tried.

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