"No GATT proxy node is connected" error when configuring model publication via nRF Mesh app

[badrbouslikhin]

Description:
I am unable to change the destination of a Sensor Server element (Model Publication). When attempting to write the configuration, I receive the error:

But I know that a GATT proxy is connected and the network key is correctly bound to that device.

Background & Context:

• Everything was functioning correctly around July 2025, apart from the nRF Mesh app update, nothing changed.
• I am connecting to the mesh via a specific node (e.g., 0x00E7) which acts as the GATT Proxy.
• The connected proxy is not one of the main Relay/Provisioner nodes but a standard mesh node.
• The same operation works fine with the Android version 3.3.8 of nRF Mesh.

Environment:

• App Version: 4.6.0 (iOS)
• OS: iOS 26.1
• Device: iPhone 14

Steps to Reproduce:

1. Connect to this node via the nRF Mesh App.
2. Navigate to a Sensor Server model on an element.
3. Attempt to change the Publication Destination.
4. The error appears immediately.

This is rather urgent as we relied heavily on the nRF Mesh app. for our operations.
Thank you for your support!

[badrbouslikhin]

I believe this is probably related to this PR #645

[philips77]

Hi,
So the issue here is that your device does't get a response to Proxy configuration messages. Note, that the Proxy Filter is empty. As a side effect, the app doesn't know which Node it is connected to.

What you could do to investiigate?

If you have access to a Mac, open Console app, connect the iPhone with a cable, enable Info and Debug in the menu, select the iPhone on the left and click Start streaming in the middle of the screen.
Then set up a filter subsystem=com.nordicsemi.nRFProvisioner. This should give you logs from the app.

I suspect, that the connected Proxy Node is ignoring messages sent from the iPhone due to sequence number being too low.
Try Settings / Provisioners / This Provisioner / Edit and change the Unicast Address to a new unique number.

Then reconnect the the Proxy Node and try again.

[badrbouslikhin]

Thank you for your feedback!
Here are the logs I get:

com.nordicsemi.nRFProvisioner	debug	13:52:30.439702+0100	nRF Mesh	Connecting to Harmonia v2...
com.nordicsemi.nRFProvisioner	info	13:52:33.428683+0100	nRF Mesh	Connected to Harmonia v2
com.nordicsemi.nRFProvisioner	debug	13:52:33.428711+0100	nRF Mesh	Discovering services...
com.nordicsemi.nRFProvisioner	debug	13:52:34.322237+0100	nRF Mesh	Service found
com.nordicsemi.nRFProvisioner	debug	13:52:34.322278+0100	nRF Mesh	Discovering characteristics...
com.nordicsemi.nRFProvisioner	debug	13:52:34.681710+0100	nRF Mesh	Data In characteristic found
com.nordicsemi.nRFProvisioner	debug	13:52:34.681849+0100	nRF Mesh	Data Out characteristic found
com.nordicsemi.nRFProvisioner	debug	13:52:34.681881+0100	nRF Mesh	Enabling notifications...
com.nordicsemi.nRFProvisioner	debug	13:52:35.250896+0100	nRF Mesh	Data Out notifications enabled
com.nordicsemi.nRFProvisioner	info	13:52:35.250936+0100	nRF Mesh	GATT Bearer open and ready

I've got the same issue after changing the unicast address of the provisioner.

[philips77]

For some reason the device doesn't send you the Secure Network beacon.
Do you get it when you connect with Android nRF Mesh, or nRF Connect after enabling notifications?

[philips77]

Here are the logs that should show up:

Bearer	info	Central Manager state changed to .poweredOn
Bearer	debug	Connecting to Mesh Light Switch...
Bearer	info	Connected to Mesh Light Switch
Bearer	debug	Discovering services...
Bearer	debug	Service found
Bearer	debug	Discovering characteristics...
Bearer	debug	Data In characteristic found
Bearer	debug	Data Out characteristic found
Bearer	debug	Enabling notifications...
Bearer	debug	Data Out notifications enabled
Bearer	info	GATT Bearer open and ready
Bearer	debug	<- 0x010100C00EB07AF59889E500000000F1F0BAE4B0F17900
Network	info	Secure Network beacon (Network ID: C00EB07AF59889E5, IV Index: 0 (normal operation), Key Refresh Flag: false) received (authenticated using key: Primary Network Key (index: 0))
Proxy	info	New Proxy connected
Proxy	info	Sending SetFilterType(filterType: Accept List) from: 3366 to: 0000
Network	info	Sending Control Message (opCode: 0x00, data: 0x00)
Network	info	Sending Network PDU (ivi: 0, nid: 0x0F, ctl: 1, ttl: 0, seq: 24, src: 3366, dst: 0000, transportPdu: 0x6F1D, netMic: 0x13822CE6709B69D2) encrypted using Primary Network Key (index: 0)
Bearer	debug	-> 0x020FC1A9E36234FBDC3E6F1D13822CE6709B69D2
Bearer	debug	<- 0x020F30EE98A46F945808A3921126023E973477FF47E6
Network	info	Network PDU (ivi: 0, nid: 0x0F, ctl: 1, ttl: 0, seq: 513, src: 3339, dst: 0000, transportPdu: 0xA3921126, netMic: 0x023E973477FF47E6) received
Network	info	Control Message (opCode: 0x03, data: 0x000000) received (decrypted using key: Primary Network Key (index: 0))
Proxy	info	FilterStatus(filterType: Accept List, listSize: 0) received from: 3339 to: 0000
Proxy	info	Sending AddAddressesToFilter(addresses: Set([49152, 13159, 13158, 65535])) from: 3366 to: 0000
Network	info	Sending Control Message (opCode: 0x01, data: 0x33663367C000FFFF)
Network	info	Sending Network PDU (ivi: 0, nid: 0x0F, ctl: 1, ttl: 0, seq: 25, src: 3366, dst: 0000, transportPdu: 0x1E812AD0A282A2B2E7, netMic: 0xC061B2F9D0510DC8) encrypted using Primary Network Key (index: 0)
Bearer	debug	-> 0x020F7E8F5B91181164BF1E812AD0A282A2B2E7C061B2F9D0510DC8
Bearer	debug	<- 0x020F9C9E336659A498AF0D04C10B6FF9E22A76FB26C0
Network	info	Network PDU (ivi: 0, nid: 0x0F, ctl: 1, ttl: 0, seq: 514, src: 3339, dst: 0000, transportPdu: 0x0D04C10B, netMic: 0x6FF9E22A76FB26C0) received
Network	info	Control Message (opCode: 0x03, data: 0x000004) received (decrypted using key: Primary Network Key (index: 0))
Proxy	info	FilterStatus(filterType: Accept List, listSize: 4) received from: 3339 to: 0000

[badrbouslikhin]

What do you mean by: Do you get it when you connect with Android nRF Mesh, or nRF Connect after enabling notifications?

With Android nRF Mesh, everything works as expected, no issues there. And the devices firmware hasn't changed since last time it worked with the iOS app.