Can’t Login To Dashboard

I’m experimenting with this plugin and after making some settings and tweaks I have now discovered that I can’t login to the WP dashboard as the admin anymore. I get re-directed to a blank page. The only way to get back in is to go and change the plugin folder name in my file manager.

Not a good start! What am I doing wrong? I have unchecked the “restrict dashboard access” options under advanced settings. Doesn’t make any difference.