Error on registration

Hello I am setting up my Membership site. I have configured my membership levels, subscriptions and a visitor level. However when I try to test the sign up process using the Popup Registration Form, after clicking a subscription and expecting to see the popup form, I get a popup with the following error and I won't proceed to the welcome form.

Warning: call_user_func_array() []: First argument is expected to be a valid callback, 'membershippublic::popover_sendpayment_form' was given in /home/tawanda/public_html/wp-includes/plugin.php on line 405

If I user the "Original Membership form" option, I get an error "Page not found" as it will be pointing to a page: I don't know why it points to that page when my welcome page is set as just "Welcome". Please see screenshot.

I have tried several things including putting no restriction options on my levels including the visitor level to no avail. My subscription is active, the level is active, one payment gateway (freesubscriptions is active). Please advise as soon as possible.