icplays, thanks for that fix. We’ll definitely make a note of that for future issues likes this – unfortunately sometimes TML and PMPro do not play nicely but that be fixed sometimes through hooks and filters. You could try this to disable the redirection on login completely:
add_filter('pmpro_login_redirect_url', '__return_false');
or to stop PMPro redirecting the register page with:
add_filter('pmpro_login_redirect', '__return_false');
It’s also possible the “Apply Discount Code” button is timing out, so you can change the AJAX timeout with the pmpro_ajax_timeout filter.
If you are receiving a blank white screen, you can turn WP_DEBUG on in your wp-config.php file and see if you get any specific errors so we can get more information.
You can also check to see if it is a plugin or theme conflict by deactivating your plugins one by one and/or switching to a default theme such as twentyfourteen.
Additionally, if you want, we can take a look at your site if you become a PMPro member and post on the member support forums.
Hope this helps!
Thanks,
Jess