WAC510 Won't Upgrade Firmware - Currently v1.5.3.6

I noticed that my WAC510 (Insight Managed) wanted a new firmware upgrade (v9.5.3.2).  I tried to apply it online and it kept failing but did not tell me why.  I rebooted and tried again and still failed.  I manually downloaded the firmware file and tried to update via the web.  I keep getting "Select a valid firmware file format."  I tried multiple older firmware versions but keep getting the same message.

I did a factory reset and reconfigured in my location for Inside Managed.  On IM it shows as downloading firmware.  I've tried rebooting but still the same.  Otherwise, the AP seems to be working.

From the web, it shows the firmware is currently v1.5.3.6.  I've tried everything starting from v1.5.3.10 and it won't take the update (same valid firmware file format error).  Insight Manager says it has the latest firmware.

I'm not sure what else to do at this point.  Anyone have any suggestions or solutions?

Thank you!

-Tim