Are you unable to login into Dev Org? Try this!
I was going through the Lightning Trailhead, which at one point wanted me to change my domain and promote it to the users. After this step I am unable to login into the same Dev org. Since it is a dev org, there is nobody else that can login and help me. I tried resetting the password, and every time I try to login it just redirects me to the same login page. I changed the password 5 times and still have no success.
Any suggestions?
I was facing a salesforce developer login issue for many days. The problem was that I forgot to deploy the custom domain to users after it was approved. And if you go to My Domains settings, from there you need to finalize the process by deploying the my domain to users. After that the login.salesforce.com started working for me.