Locked out from backend

Replies: 0

Today I moved a domain name, the website was ready and all-in-one wp security and firewall was configured.

After activating LetsEncrypt on the server, I have no longer access to the WordPress backend.
If I call http://www.domeinaam.nl/newname, the url changes to http://www.domainname.nl/wp-admin

I am locked out. Can I remove the all-in-one-wp-security-and-firewall plugin with FTP without problems and start over again? Or what can I do?

Thanks in advanced,
kind regards,
Begur