Unable to access wireless network via AC2200 after power failure and power has been restored

Hello All.  After a brief power failure at my home, I was unable to log into the extended network.  I was, however able to log into the wireless network through the AC5300 router.  So I assume that the issue was with the AC2200.  Using www.mywifiext.com, I was able to reconfigure the AC2200 after using a factory reset on the unit itself.  Set up the user name, password and security questions as prompted.  Tapped into existing wireless 5G as prompted.  Save all credentials as prompted.  After removing the AC2200 from powe rsource, and relocating, plug-in and AC2200 reboots-I am unable to log into the device with saved credentials from a Iphone 6S Plus. Get error that the password is incorrect or no error at all from the iPhone.   Reconfigured the AC200 as described above, but this time, I used an extended network cable to the device to the location where the device will stay.  Meaning, there was no un-plugging and rebooting the device.  No powewr interuption.  The AC2200 works fine.  So the question is-what am I doing wrong where the AC2200 is not retaining the password after configuration (save) and un-plugging the device? Using above web address on W7 latest build.  All firmware updated.   I thank all who assist.