My RE220 range extender suddenly stopped working. It might have been after a brief power outage, but I'm not 100% certain of the timing. 
 

I'm trying to set it up again but on the app it just keeps telling me that it is “Unable to join network TP-Link_Extender” and I can't proceed any further with the setup. I had no problems setting it up originally. 
 

While trying to set it up the power light stays solid for a few seconds, then blinks for a few seconds, then all the lights turn on momentarily (including one that is red) and then the cycle starts again. 
 

I have reset the unit multiple times, but nothing changes. 
 

I'm at a loss.