The site opens correctly in other browsers, but she hasn't used those browsers.

I suggest removing that bookmark and creating a new one.

The same thing happens when I type the url direct. Typing mail.google.com does the same.

Log out of your daughter's account. Then log into your own.

she isn't logged in. I can't get to the gmail server. For some reason, it reroutes to the ACC mail server, every time.

Try first going to google.com instead of going directly to Gmail and check the accounts in the top right. If your daughter's account is selected or logged in, switch to your own account and then try going to your email.

Went to Google.com. She wasn't logged in. When I clicked on Sign In, it took me to ACC mail