[Membership 2 Pro] registration complete goes into blank page

after adding a redirect php file for another thank you page for one of the memberships "All in one" goes into blank page instead of going into regular thank you page:

from

https://dietgirl.com/register/?step=payment_table&membership_id=27053

redirects to :

https://dietgirl.com/registration-complete/?ms_relationship_id=30038