I can't for the life of me figure this out, and I've searched the forums high and low. I'm setting up a new installation, and everything is working just fine, except one subdomain keeps redirecting to the login page, or if you are logged in, to the admin area. I've found all kinds of posts about trying to login and it redirecting to other pages, but not the other way around. To be clear, I can't access the site itself, _only_ the admin.
I have 2 other subdomains that work just fine. I don't have many plugins installed, and those that I do have installed I've tried removing from mu-plugins, and that didn't change the behavior. And as I said, the other two work just fine. I don't get any errors about it being private, and I've tried setting the Site Admin option to public and saving just to make sure (I did at one point, using the sitewide privacy plugin from wpmu dev, have it set to only logged in viewers). I've looked through the database, and for blog_public the value is '1'.
I've also tried numerous times to dump cookies for that subdomain, as well as all associated with the domain. Any suggestions?