All has been well for sometime. Suddenly something has broken access, with now everyone other than Admin getting access denied when the log in. It appears the profile.php is blocked, which I had done before, but having resest everything and removed all the blocks setting the plugin back to defaults, I still cannot get non-admins logged in, it still says access denied. The only fix, it to disable the plugin when it works normally again.
I did notice and apply an update first thing this morning. Not quite sure what to do other than leave it disabled at the moment and lose the access control I had, but would welcome any ideas.
I have made a lot of other changes recently so could well be something else has caused this, I'm just not sure of how to find out what/how.