The problem: You install Magento on a professional web hosting with a proper domain name. You been given a URL for your admin login.
You enter the correct admin username and password but it just refresh and does not log you in. You can try use the "Forgot your password?" option to change your admin password, in which I did tried, but it still doesn't work.
Applicable to Magento version 22.214.171.124
Solution: Try use Firefox or Opera browser. I've tested out on my own web hosting and found this problem occur when using IE and Chrome. Perhaps the Magento team will fix this issue soon, and for the time being, you'll need to use a different web browser.
I wonder would this happen to existing user account at store front. If it does, existing store running Magento could end up lossing some business.