I came online searching for this because it is happening to a new site I set up on my multisite. If the domain is set to be primary domain I can not login. No error message given.
I have to go into the multisite, remove it as the default and then I can log into that blog.
it only seems to be happening on a new site I set up. This is what shows up in the browser
'humblebumble.com/wp-login.php?redirect_to=http%3A%2F%2Fhumblebumble.influencer.biz%2Fwp-admin%2F&reauth=1'
I don't know if that makes sense or not. It is telling the main domain to redirect to the multisite domain and nothing happens.