Nighthawk LTE Mobile Hotspot Router ATT

My orignial MR1100 was stolen in Phoenix 3 weeks ago.  I have received a replacement and trying to do setup a http://attwifimanager/ per the instructions, I get redirected to spam sites (apple tech spent 30 minutes getting rid of crap). When I go to http://192.168.1.1 it states can't find page.   AT&T tech support spent 2.5 hours trying to help me and finally gave up.  When I could get into the site, it would not allow me to put in the default username and password.  I tried my previous (stolen) Nighthawk username and password to no avail.  I can't get to the setup site to get my Nighthawk going.  When I do get to the site, it won't take username and passwords.  Just keeps saying they are incorrect.  I've tried using admin as the username and saying I forgot password and it still stays incorrect username or password. Can anyone help?