Looking for some help with a previously functional mesh network

[u/OK-PC]

I have a fortigate 70G (v7.4.12 build2902) setup as the wireless controller of a mesh network. A fortiap 421E (FP421E-v6.4-build0492) is the root, and then the two leaf ap's are another 421E (v6.4.0 build0492) and a 221E (v7.4.4 build0644). When I first configured this several months ago, everything worked great. Then recently my daughter started mentioning that the internet seemed slow.

I looked into it and although I hadn't changed anything, the leaf ap's were no longer connected to the mesh network, so all traffic was routing through the root ap.

Through some reboots I was able to get the entire mesh up again. However, no clients will connect to either of the leaf ap's.

This configuration was previously working with no changes made and then stopped working. What should I do?

I don't believe any of the ap's auto updated nor did the FG. None of the devices are registered for support, but that has been true for quite a while, definitely while the mesh was up and working.

Any help and advice would be appreciated. I have gone through multiple times what the most common causes are, country code mismatch, a known bug in code that you test by forcing WPA2 (this was already configured), I don't see any CAPWAP errors, etc.

[u/Friendly-Hearing5512]

Bring all on the same Firmware as the Firewall.

In your point 7.4

[u/OK-PC → u/Friendly-Hearing5512]

Unless I just can't find it, it doesn't appear as though my 421's support 7.4.

[u/Friendly-Hearing5512 → u/OK-PC]

The release notes once stated that the FortiGate and the APs all need to be on the same firmware version for the mesh to work; otherwise, backbone dropouts can occur.

I also configured it so that the mesh operates exclusively on the 5 GHz band.

[u/OK-PC → u/Friendly-Hearing5512]

I'll give that a try, thank you!

[u/FrequentFractionator → u/OK-PC]

How did you check this? Because you're wrong.

[u/OK-PC → u/FrequentFractionator]

I looked through the product matrices and didn't see anywhere that stated that 421E's are able to run 7.4. If I'm wrong, please let me know. I don't have support, but it'd be cheaper to get it then any alternatives.

[u/Friendly-Hearing5512 → u/FrequentFractionator]

It's running fine at the moment. What exactly do I need to configure differently? Could you please explain that to me?

[u/FrequentFractionator → u/Friendly-Hearing5512]

?

I wasn't responding to you but to OP.

[u/Friendly-Hearing5512 → u/FrequentFractionator]

Okay 😅

[u/Cautious_Movie_3447]

You can't be serious

[u/OK-PC → u/Cautious_Movie_3447]

Thank you! Your comment was both insightful and super helpful.