In the not too distant past, when a plug in was acting up and I could no longer get access to the dashboard via /wp-admin or /wp-login all I had to do was to FTP in and remove (delete) the offending plugin... presto, /wp-admin worked again.
On two of my domains, each has a different plugin causing a problem, FTP in and delete now causes more problems, not less.
on one domain the plugin wp-geo is a likely culprit
is the one with WP Geo removed (via FTP delete.
now look what happens when you attempt
I'm guessing a path problem?
a manual edit of /wp-config perhaps?
Or am I going to have to get my hands dirty with PHP Admin (I hope not)
on another wp3-total cache is the probable cause of a borked website.
FTP and delete did not fix either domain