Problems setting up new APX

Hello Mateusz Bender,

Thank you for reaching out to the community, the error may indicate a handful of problems:

1) A power injector issue, if used
2) A switch PoE issue, if used
3) Defective cable
4) AP hardware issue

In order to rule out the first points, please try to:

1) Use a different power injector
2) Connect the AP to a different switch, or use a power injector
3) Use a different cable

FYI: Another AP has been used on the same port using the same power injector. Granted, it was a "lesser" device (AP55), but still.

1) If the AP starts up and chimes in correctly at the start can it really be a power issue? Additionally another Sophos AP on this PoE injector worked correctly.
2) N/A
3) If another AP on the same port (using the same cable) works, can this be a cable issue?
4) Quite possibly? Any other logs?

I can also add that I if I did not set up the VLAN on the AP then it registered correctly and I assume I would be able to set up new WiFi networks then. Unfortunately we need the VLAN configuration...

Have you tried a VLAN config by directly connecting the cable from UTM VLAN interface to directly to access point without a switch in between ?

No, and quite frankly I don't think I can without being very disruptive to everyone at work. Plus I'm not sure what that rules out. If you're suggesting the issue is with the Cisco switch in the middle then my counter is that another AP (AP55) worked in that exact same spot previously without issues (same config). Also of note - we have one OTHER Sophos AP on another port on the same switch with the same configuration and the same model of PoE injector working just fine.

If the AP needs more power than AP55 and APX320 (which is our other Sophos AP) then it could very well be the PoE brick. However it's worth noting that I've also tried to just assign the new AP to a VLAN without assigning any WiFi networks...

So, does the AP get the IP address from the DHCP ? And any registration issue for the AP ?

Initially, yes. It was able to grab an IP from our own DHCP without issues. At that point the AP shows up as an unauthorized device in URM web interface.

Following that I was able to authorize it without setting any networks and changing the VLAN config.

After changing the VLAN config in UTM web interface the device appears to go through the re-config process but fails with the error provided in the original post, and from that moment it's "gone". It never receives a new IP from the new VLAN (DHCP for VLAN 11 is handled by the UTM itself).

And the DHCP server is configured on UTM 9 or on the windows ?

DHCP on VLAN 1 is a Windows Server DHCP. DHCP on VLAN 11 is on UTM.

Did you try to enable AP-Vlan-Tagging and setting AP-Vlan at AP-Level and AP-Group-Level already?

Also, I would try to set VLAN1 as Tagged VLAN at the switch-port while the AP is "lost".

May be the following article can help: https://support.sophos.com/support/s/article/KB-000034799?language=en_US