[Plugin: WP-Members] Widget login button doesnt work

hello,
I am using wp-members for a widget on one of my pages, every time a user tries to login and presses the ‘login’ button it just redirects them to a page which doesn’t even exist. Im new to WordPress and not really sure how to overcome this. Can anyone please help me?
The page is located at:
https://www.wigan-pier.co.uk/OBB/?page_id=101
try clicking the login button to your right and you will see what happens.
Any help would be really appreciated. Thank you!!