Quick answer: Find the message you see on screen and follow the fix for it. You change an iPad between Master and Slave in Settings > Connection, under Server Mode.
Use this guide when Nomni POS won't let you change an iPad between Master and Slave, or won't connect a Slave to the Master. Find the message you see on screen and follow the fix. You change modes in Settings > Connection, under Server Mode.
"Enter validation PIN" / "The PIN you entered is invalid"
Changing to Master or to Slave always asks for a validation PIN. The PIN is provided by Nomni Support, so contact us when you need to switch an iPad to Master or Slave.
"Unable to Become Master"
"POS already has a Master. Disconnect from it to be promoted to Master": this iPad is still connected to a Master. Remove the Master from this iPad's Server List with the ×, then tap Master again. Only one iPad should be the Master.
"POS is currently looking for a Master" or "POS is currently trying to connect to Master": wait a few seconds until the spinner stops, then try again.
"Running multiple Masters on the same network may make the POS system unstable!"
Another iPad on your network is already the Master, and the message shows its device name and IP. Don't continue unless you're replacing that Master. Keep one Master and set every other iPad to Slave.
"Unable to switch to Slave mode"
"There are unsynced orders in the system": sync your orders first. See How do I sync Unsynced Orders?
"There are unsettled orders in the system": settle or close every open order on this iPad first, then try again.
"Please Disconnect Razor in Device Options": go to Settings > Device Options, disconnect Razor, then try again.
Sync unsynced orders
Follow these steps:
Check the iPad is connected to the internet.
Tap the unsynced orders button in the top bar. It shows how many orders are waiting.
Wait for the count to go down to 0. Leave the app open.
If the count doesn't change, go to Order History and tap the sync button. This also sends orders older than 3 months, which the automatic sync skips.
Full guide: How do I sync Unsynced Orders?.
"⚠️ Switching to Slave Mode: This action may disconnect all devices"
Devices are still listed in this iPad's Server List. Remove each one with the ×, then tap Slave again. After the change, reconnect the other iPads to the new Master.
"Local Network Access Required"
Nomni POS needs Local Network permission to find the Master. Tap Open Settings (or go to iPad Settings > Nomni POS) and turn Local Network on, then go back and tap Retry.
"Unable to search for Master POS" / "Unable to connect" / "Unable to Auto Connect."
The iPad isn't on a network, or it can't reach the Master. Check the iPad is on the same Wi-Fi as the Master, then type the Master's DEVICE ADDRESS (for example 192.168.9.20) into the box on the Slave and tap Connect. Typing the address is more reliable than Auto Connect. For more checks, see Slave iPad not connecting to the Master: troubleshooting.
"Device limit exceeded"
You have more devices connected than your subscription allows. Remove devices you no longer use from the Server List, or contact Nomni support to change your plan.
“Failed To Complete Order: Unable to get invoice number from Master POS”
The payment went through, but the Slave iPad couldn't get an invoice number from the Master to finish the order. Don't take payment again. Check the Master iPad is on, Nomni POS is open on it, and both iPads are on the same Wi-Fi. Then tap TRY AGAIN. Printing and emailing the receipt unlock once the order completes.
“Failed to select table: Table map information could not be retrieved from the Master POS. Please retry.”
The Slave couldn't get the latest table map from the Master. Tap Retry. If it keeps failing, check the Slave is connected to the Master (Settings > Connection).
“Table … overridden by …: Please sync with master to get the latest version of map”
Another iPad took over this table while you were using it. The message names the table and the other device. On this iPad, go to Settings > Sync and tap MASTER SYNC to get the latest table map.
Nomni POS for Android: Master and Slave messages
“Connection to Master POS lost. Please reconnect to continue” or “Unable to connect to Master POS, please check the connection”: check the Master is on with Nomni POS open, and both devices are on the same Wi-Fi.
“Unable to send the order, please check the connection with the Master Pos”: the order wasn't sent. Reconnect, then send it again.
“Activating table timed out, please check on the master Pos if the table was activated” or “Starting order timed out, please check on the master Pos if the order was started.”: check the Master before trying again, so you don't open the table twice.
“The order has been loaded on the other POS. Are you sure to override it on the Master POS?”: another device has this order open. Only override it if nobody is still working on it there.
“Communication with Master Pos error, unable to load the order”: reconnect to the Master, then open the order again.
Still stuck?
Contact Nomni support with your Store ID, which iPad is affected, the exact message, and a screenshot of Settings > Connection.
You can also email support@nomni.ai or call 1300 445 483.