If you have issues with the Paypal Pro form not redirecting, you should ensure that within the code for your Paypal pro form (generated by OptimizeMember) you include the success attribute:
Inside the code you need to use:
success=”http://your-thankyou-page.com”
This should be included within the form code generated by OptimizeMember
The settings in Paypal should be set as per the instructions inside the OptimizeMember sections for autoreturn and PDT settings otherwise you will encounter other issues.