My AX5400 has worked fine for about 3 months and now it has suddenly started to just continuously cycle through the start up process.  The lights on the front come on momentarily and then the go off and the power light flashes.  After the power light flashes for about 30 seconds, it goes off for a few seconds and the process starts again.

Nothing happens when I try to do a reset using the button on the back of the unit.

Also, I found that it is broadcasting a SSID TP-Link_CFxx which does not match the SSID on the bottom of the device or what I had set up.