My AP30 would have connectivity issues whenever I updated the firmware on my XG. Other than that, it was rock solid. It was posted elsewhere that the AP30 is an end-of-life product and no longer supported. So, I purchased an APX120. I connected it last night. It sat with a solid red light for a few minutes before being recognized by the XG. I did a brief test to ensure that the devices were connected via WiFi. They were, so I left it.
While I was away during the day, the APX120 continually dropped connections to the point that it was not possible to browse websites. I could not find any settings to better this.
Tonight I decided to reset it by pressing and holding the reset button. The manual says to hold the reset button until the LED blinks red. I tried this but it never got to the blink red state. It stayed at solid red. So, I released the reset button. It then went into a cycle of solid red followed by flashing green and then solid red again. This lasted for 5 minutes. Since there was absolutely no progress, I disconnected the power and plugged it back in after a minute. Now it just sits with a solid red light. At no point did it flash red which would have indicated it was doing a firmware update.
I've replaced the ethernet cable in case something went wrong when I was unplugging things, no change.
I've tried the reset button again, but nothing. I've left it unplugged for 10 minutes and no change.
I've rebooted the XG and no change.
It would be really nice if there was some type of feedback on the APX120 or the XG to let me know what is going on or not going on. Troubleshooting appears to be limited to "the light is red = something is wrong".
At the moment, I have an expensive red LED light for my office.
After some back and forth with Sophos support, they have issued me an RMA. The new unit is due to arrive tomorrow. I was not pushing the issue too hard, as I had put non-Sophos APs into service. Over the course of troubleshooting, Sophos support determined the APX120 had become bricked.
The Sophos support was very good. Likely the best that I've experienced insofar as their attention to the issue and desire to resolve it.