I need help. I have the dead white screen after lockdown wp admin

Dear Supports,

I recently upgrade my wordpress site (www.vietnamdmc.com) and I can no longer login into my site. The url I created from Lockdown wp admin is the white screen of dead and the wp-admin page show error “access not allowed”.

My lockdown wp-admin is http://www.vietnamdmc.com/agents-login

Please send me the guideline how to deactivate the plugin and access my dashboard as I need to change something on my website urgently.

Thanks so much for your help.

Tri Nguyen.

https://wordpress.org/plugins/lockdown-wp-admin/