Occasionally the attached page will show up on my site - i have tried to stop it being linked to as much as possible but on the Register M2 page it will come up if they click the link at the bottom saying 'already have an account'

The problem is when you then click on the sign in link on that page, even though the login details are correct it takes you to the 404 page and does not log you in.

Also if you click the lost password link on it nothing happens

Any idea of a fix for it?