when I adopt it in goes through an update and give me that error multiple times

This fixes a breaking version mismatch where the Network App 10.3.55 fails to communicate with nodes stuck on the 5.0.x OS branch.

**The 60-Hour Battle: UCG-Max & UX7 Mesh Instability**

I’ve spent the last week in the trenches troubleshooting a "release gap" issue that nearly soured my first experience with the UniFi ecosystem. I want to preface this by saying **I have a very strong networking background in industrial automation and PLC programming; while I am new to the UniFi interface, I am certainly not a novice when it comes to traffic, protocols, and hardware integration.

To document this "broken" update path, I used Gemini AI Live video to assist me through the troubleshooting in real-time. I also had the AI generate this summary by distilling my technical support logs and our live session to ensure all the technical "smoking guns" are accurately recorded for the community.

**The Experience: From "Awesome" to "Broken"**

I recently picked up a UCG-Max and three UX7s. The initial setup was incredibly smooth—I was 75% through my configuration, everything was working perfectly, and I was actually super happy with how awesome the UI was and how stable everything seemed.

Then, the update to Network Application 10.3.55 was pushed. Immediately, the mesh quit working. My UX7s being used as mesh nodes entered a constant "Action Required" loop. I tried setting them up individually, but the same issues occurred with every single unit.

**The Conflict: Support vs. The Logs**

I spent days in contact with Ubiquiti support. While their staff is knowledgeable in text chat, the lack of voice support for brand-new equipment is a major pain. Initially, support claimed they couldn't simulate this in their labs and insisted 10.3.55 was compatible with UX7s on OS 5.0.16.

After I redundantly validated the crash twice and pushed for escalation, their team identified the "broken link" between the gateway and the UX7s. The logs tell the real story:

**The Technical "Smoking Gun":**

The 10.3.55 update contains a configuration rejection where it flags the mesh_uplink_1 key in the device payload as invalid.

**The Broadcast Failure:**

Because this key is rejected, the gateway fails to push a valid mesh config. The hostapd service on the UX7s fails to initialize, forcing the 2.4GHz and 6GHz broadcasts into a permanent "Link DOWN" state.

**VLAN/DHCP Chaos:**

Because the virtual access points (VAPs) fail, VLAN-tagged interfaces are stripped from their bridges. This caused my wireless devices on **VLAN 20** to suddenly be assigned IPs from the **VLAN 10** scope because the system was issuing NAKs and failing to route correctly.

**The Version Trap**

The core issue is that 10.3.55 is not compatible with versions older than UniFi OS 5.1. While the UCG-Max can run 5.1.x, the **UX7s are capped at OS 5.0.16**—even in the Early Access channel. This is a major version-coordination failure on Ubiquiti's part.

**The Fix: Manual Rollback**

The only way to **fix the mesh and AP issues connected to the UCG-Max** is to force the entire system back to the 5.0.x branch via **Recovery Mode**.

1. **Flash UCG-Max to:** UniFi OS **5.0.16**.

2. **Ensure Network App is:** **10.0.162**.

3. **STRICT RULE:** Turn off **Auto-Updates** immediately. Do not update until Ubiquiti releases a coordinated 5.1.x (or higher) OS for the UX7.

**The "Legacy" UI Battle: Firewall & Zone Builder**

Be prepared for a fight once you roll back. The 10.0.162 version is noticeably slower and more sluggish than the 5.1.8/10.3.55 branch, and the "Firewall Builder" is incredibly buggy.

**Firewall Workarounds:**

I found that the standard builder was doing things that simply did not make sense logically. In the end, switching to the **Zone-Based Firewall (Zone Builder)** was the only way to make the rules function correctly.

**AI Verification:**

Having *Gemini AI* watch the screen via video was the only way to confirm the UI's nonsensical behavior and develop workarounds. Even the AI could see that the UI was reporting one thing while doing another.

**Final Takeaway**

Ubiquiti has a beautiful product and I'm impressed with the potential, but they are trying to rush things and go too fast. Promoting an application version to the "Official" channel before the UX7s are ready to support it as mesh nodes is a major oversight. They need to be more cautious and ensure stability across device families before pushing "stable" updates to new users.

Hopefully, this saves someone else the 60+ hour battle I just went through.

After around 18 hours I noticed the WPA2 connection had changed to Open. This was a bit of a shocker!!

The unit became extra sluggish in responding to the Network app.

(The Password field was asterisks not blank).

Nothing was changed on the networking settings since it was first setup. Firmware shows no updates available..

I “forgot” the wifi on two different devices and was then able to connect to the unit Open Wifi, even though when I went into UTR settings “WPA2 only” was still set for the custom WiFi with a long string of asterisks.

The strange thing is, my device had originally still connected to it even though it should not (MITM etc) as the iPhone (26.4) SSID settings were untouched WPA. The custom SSID and password is the same as we have for another device we use when camping and hence our devices have had this setup well before the UTR.

The second device still showed the padlock on the SSID, but when forgetting and reconnecting on that device it dropped the padlock and saw it as Open and connected.

The UTR appeared to be serving both open and WPA2.

I tried to get a support file but the UI was sluggish and the download was zero bytes. I restarted the unit and the network remained the same, but did get a support file (attached).

This is obviously a concerning issue, and would ask other UTR users to check if using Custom WiFi name that the wireless security is still effective.

its currently powered off but plan to do a Factory reset and try again monitoring closely…

This may be because the clients of WAN1 have been assigned an IPv6 address and naturally prioritize IPv6.

The 5GMax is connected via a POE LAN port and does not receive an IPv6 address, even though my provider offers this service.

Does anyone have any idea how to debug this?

Thanks!

I have installed my home network, I have a Gateway Ultra and Im leaning how to configure it.

At the moment I bought a couple of Shellys and I installing a computer with Home Assistante.

From the research I have done I should create a separate network for my IOT stuff, and implement rules so that:

Regular Network comunicate with IOT allow

IOT to Regular Network disallow

I have been looking at all the options but I think I need some guidance to achive this. Can anyone give me a little help?

Another question is the Home Assistante computer, should I connect a second network adapter so that one port comunicates with the IOT and another to the Regular?

Thanks in advance

• AP model(s) - U6-LR & U6-Lite
• Previous AP release version - 6.7.10
• UniFi Network application version - 9.1.118

Rolling back to 6.7.10 resolved the issue.

1. When iPhone is connected to U6+'s 2.4G over a long distance and moves closer to the AP, it will disconnect and then reconnect when switching from 2.4G to 5G, instead of using roaming mode.

2. When BSS Transition is enabled, roaming between APs is not possible.

3. Minimum Data Rate Control setting for manual roaming will be more aggressive.

4. I have changed several versions of U6+, but the roaming abnormality problem has not been eliminated.

Site B: 2 U6-LRs. Using 6.7.12 works fine.

UniFi Network Application 9.0.114

U6+ 6.7.12

U6-LR 6.7.12

AC Pro 6.6.77

Regards

Noel

• 2 x U6 Pro
• 1 x U6+

Updated and my outside google nest cam could not connect even though the U6+ is right next to it. Tried to lock to the AP, set to only WPA2 no joy. In the end factory reset the U6+ and re-adopted and it connected. Weird never seen that before.

I've a simple network, a cloud gateway ultra with a U7 access point, at home. The wifi coverage in my garage is not good and I am looking for a solution to extend the coverage.

Is there any access point that can mesh with my current U7 AP, without Ethernet cable? All access points in unifi store have only RJ45 socket with POE. I don't have (and cannot use) ethernet cable outside.

In the VLAN Network, I have Multicast DNS enabled, and IGMP Snooping disabled. In Network, I also have "IoT Auto-Discovery" enabled and "Multicast Filtering" disabled,

In WiFi, I have "Multicast Enhancement" enabled, and "Multicast Broadcast Control" disabled.

How do I configure a network taking 2.4, 5 and 6GHz but deactivate 2.4GHz on every second AP.

So that in this row all APs make 5 and 5GHz, but every second makes 2.4, 5 and 6GHz.

I found in the iOS app where I can disable 2.4GHz but when I click save it fails - in the Unifi.ui.com web is this thistle not available.

someone knows?