If you are onsite or through someone on site, when this happens again check to see what the LEDs are doing. If admin login is enabled on the APs, log into their GUI and check the status/wireless settings.
I am not familiar with the FortiCloud service as all our FortiAPs are managed by Fortigates, but I would think you should be able to remote reboot them instead of modifying their configurations.
Off the top of my head - wifi (2.4 and/or 5.0) interference, rogue APs, issue with "hand offs". If the APs are sharing/using the same configuration or channels - try putting them on different channels.
For a time this problem disappeared....Now is back.
Leds are all green, fortiAP status is OK. But any device is able to connect. When i try, it says password is wrong (Is not).
I connected another FortiAP, and still not working, i tried to reboot, and doesn't work. The only thing i see by now, is change the maximum number of clients connected to the APs (Doesn't matter the number).
I observed a similar issue, also clients suddenly getting authentication failure. I only fixed it by editing the passphrase in the fortiap cloud (just edit, enter same passphrase again). Apparently this triggers reconfiguration.
I had this 3 times now, with some days or a week in between. Very annoying. Last Friday I have created a support ticket and today I provided debug info.
Today it happened around 2 hours ago, probably at the same time as yours?
Maybe some action done at FortiAP cloud?
I am on the EU version. In the log reporting I saw an ap-join log entry some time before. (in all cases)
Oh, i hope you can get some information and share it!
By now, i created a new SSID with the mesh link option enabled....looks like this is not happening, but now all devices are connecting only on 2.4GHz...
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