EX2700 factory reset fails? -- can't get to new device prompt or login on mywifiext.net

I have three of these and want to repurpose them in a revised network.  After factory reset, only one of them behaved like a "new" product when connecting to it online, asking me to create a username and login which then works on mywifiext.net. On the other two, resetting (7 seconds or more with the paperclip) wiped the existing wifi network info and allows me to attach them to the new network successfully, but I have not been able to log into them administratively with mywifiext.net to update firmware, etc. -- nor do I seem to have any valid login credentials for them left over from earlier use. I get taken right to the network search page that shows up as mywifiext.COM (as opposed to mywifiext.NET). Forcing the browser to mywifiext.NET gets me a dropdown username/password request which I can't satisfy.

Is this a hardware problem with the reset button failing to clear that cached data (no matter how long I hold it in), or a caching problem on my computer's browser (since I'm attempting the same connections to different)? I want access to all three of these units so I can update firmware etc.  Thanks!