Why does my WordPress admin area work on one droplet, but not another from the same image?
I have two droplets, both LEMP on Ubuntu 14.04. They both have identical server setups (one was spun up from an image of the other, and then I changed the server_name and the file name for the site in etc/nginx/sites-available, and restarted nginx.
The only other differences are the files (I put the root in var/www/html as demonstrated in this tutorial) and the databases.
It was working great last week (on both sites). Now, when I log into WordPress on one site, it redirects (with no visible error) to the home page. I appear to be logged in, (the admin bar across the top, etc) but when I try to go to any admin-area page, I am routed back to the home page.
I've inspected every line of server side code for differences, and there are none. One site works, one site mysteriously stopped working.
I created a new user (via mySQL) with admin privileges, just to make sure it wasn't just something up with my username.
Any help would be appreciated. I'm stumped.