Unable to login to Wordpress

Starting to get extremely annoyed at this now. I have no idea what to do or why this is happening.

Issue: Unable to login to Dashboard/Wordpress admin the second time.

When going to /wp-admin the first time after install I get graphical login: Like this one: http://www.webtutorialplus.com/wp-content/uploads/2013/05/wordpress-admin-login.png

I can then edit site, change themes, etc. Do everything I need to do.

Next time I visit site, I get a popup instead which just states “http://mysite.com:80” “Restricted area” and a form for User: and Password: Whatever I type here it says ‘unauthorised’ and I can’t get in.

Solutions tried: -Reinstalled Wordpress, works once, then not again. -Reinstalled Droplet, works once, then not again. -Changed user using WP-CLI, do not help -Changed password using WP-CLI, do not help -Reset everything in Wordpress folder, can login once, then never again. -Tried from several different computers. -Tried different networks to rule out firewall issue. -Tried different browsers.

Setup: -I use Ubuntu 14 with Wordpress One-Click-Install. -I have my own domain. I use a subdomain fro the blog. -The host name of the droplet is subdomain.domain.com -My DNS is pointing A-record from subdomain to IP of droplet. -I use subdomain.domain.com/wp-admin to try to login. But same issue with /login and /admin