// CISCO · FIELD NOTICE FN63942
Access point won’t join? Check the date, not the hardware
An access point that worked yesterday now refuses to join the controller. It is probably not dead - its certificate has expired, and Cisco says that is a certainty for pre-2017 hardware.
- ● Vendor sources linked
- ● Dates checked 27 July 2026
- ● Independent — we sell no vendor’s kit
Independent, and dated. 365 Techies is an independent IT firm. We are not an authorised partner, reseller or agent of RUCKUS Networks, Belden, CommScope, Cisco or Cisco Meraki, and we have no access to their support entitlements on your behalf. Every date on this page comes from the vendor’s own published notices, linked in the source column, and was checked on 27 July 2026. Where we could not verify something from a vendor source we say “check with vendor” rather than guess.
If it worked yesterday and refuses today, read this before you buy anything
There is a failure that looks exactly like a dead access point but is not one. The access point is fine. Its identity has expired.
Every Cisco wireless device carries a manufacturing certificate proving it is genuine, so the controller will trust it. Those certificates have a ten-year life. When one expires the access point can no longer prove who it is, the controller refuses it, and you get a unit that boots, gets an address, and then just sits there.
One hundred percent. Not a risk — a certainty, on a timer. If your Cisco access points were made before 2017, this is coming for them, and it has nothing to do with whether the hardware is healthy.
Three failure signatures, three different notices
It joins, then drops, then never returns
Certificate expiry (Field Notice FN63942). Check the manufacture date encoded in the serial number first — if the unit is over ten years old and pre-2017, this is almost certainly it.
Stuck in ‘Downloading’
A separate, dated failure (Field Notice FN72524) affecting access points after 4 December 2022. Same symptom family, different cause, different fix.
Dead after a reboot, never comes back
Flash corruption stranding (Field Notice FN70330). Worth knowing about before you reboot a fleet of ageing access points on a Friday afternoon.
All three are published by Cisco, all three are free to read, and all three are routinely mistaken for “the access points are worn out”. Read the notice that matches your symptom before anyone quotes you for hardware.
What to do about it
The honest framing matters: this is a certificate lifetime, not a hardware failure. Cisco documents controller-side workarounds, and whether they apply depends on your controller platform and software version. On kit that is also past its last date of support, though, you are solving a problem on hardware nobody will ever help you with again — which is usually the moment replacement genuinely does make sense.
That is one of the few places in this guide where we will say plainly: if you are here because of FN63942 and your model is on the expired list on the Cisco dates page, replacement is probably the right answer rather than the sales answer.
// BEFORE YOU RING ANYONE
Walk the site and write down what people actually get
Our free Wi-Fi signal test runs in a browser, needs no sign-up, and scores every room. Ten minutes with it turns “the Wi-Fi is rubbish upstairs” into numbers — which is the difference between a guess and a diagnosis, whoever ends up doing the work. See also our room-by-room method.
Read next
The full guide
End-of-support dates for every model we could verify, and how to tell whether yours is actually the problem.
Cisco Aironet end-of-life
What “last date of support” actually costs you.
Working but unpatched
A different problem from broken, and a different decision.
Not sure what you're looking at?
Send us a photo of the label on one access point and the make of your controller. We'll tell you what you've got, what its dates are, and whether it's actually your problem — no charge for the answer.
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