Any help would be appreciated.

I see how that code removes the pre_get_posts filter, but I don't want to remove that filter permanently. Only inside of another plugin. I'm using the plugin WP Courses (https://wordpress.org/plugins/wp-courses/) as I need a basic course taking system. I would CoursePress but it is just too detailed. Each of my courses consists of a single video. In CoursePress I have to make a unit and a module and just through 10 hoops to create a basic course that only has a single lesson. Anyway... WP Courses has 2 custom post types. "courses" which basically allow the user to see an overview and "lessons" which are the actual content. In Membership2, I have protected the "lesson" custom post type. Now to the issue. Lessons have a custom field with the ID of the course they are associated with. So, on the single course page to know which lesson to start them on... The plugin uses WP_Query to find the lesson that has the custom field equal to the course's post_id. Because lessons are protected this query is always empty. $args = array( 'post_type' => 'lesson', 'meta_value' => $course_id, 'meta_key' => 'wpc-connected-lesson-to-course', 'posts_per_page' => 1, 'paged' => false, 'nopaging' => true, 'order' => 'ASC', 'orderby' => 'menu_order' ); $query = new WP_Query($args); if($query->have_posts()){ while($query->have_posts()){ $query->the_post(); $course_link = get_the_permalink(); break; } } How to replicate this issue: 1. Install Membership2 and create a membership 2. Install WP Courses and create a course with a lesson 3. Be logged out and view the course and then click "Start" to start the lesson 4. You will be taken to register, don't register 5. Now protect the "lesson" custom post type 6. Be logged out and view the course and then click the "Start" button - it doesn't take you anywhere because it doesn't know the lesson to send you to

I was thinking I would need to hook into the MS_Model_Member::create_new_user() function somewhere? Maybe the “wpmu_validate_user_signup” filter? Basically, if a user tries to register on 2 different subsites the plugin will allow add their existing user to the second subsite and notify them.

That plugin doesn't work. Users still get the same error. "That username is already taken, sorry. That email address is already taken, sorry." Even though that email/user has never signed up for any membership on this subsite.

I understand that... But here is my issue. User1 makes an account on blog1.mysite.com. They then go to blog2.mysite.com. They have not registered. Have not done anything. They click the register button. They attempt to register. They get an error saying that email has already made an account. Wait, what? They have never been to blog2 before. I look under "Users" and "Membership 2 -> All Members" and "CoursePress Pro -> Students" and i can't find User1 anywhere. They don't exist on blog2.mysite.com. But, they can login using their blog1.mysite.com password. Membership 2 shortcode knows who they are on blog2 even though they haven't registered. What is going on???

Any final resolution?

I figured out the issue. There is a setting in the authorize.net section that is just "Secure payments" -- which is the worst possible name for this setting. Who doesn't want secure payments??? Everybody! But turning that on makes it so the CVS code isn't used for some reason on recurring payments. I have no idea the point of that setting and it isn't in the docs. Turned it off and it worked.

Any response here? I'm having the exact issue but with authorize.net as the gateway.

Yes, there was some issue with the theme i was using when it did a loop in a loop. So, I rewrote a basic loop in a loop plugin and it is working now.

Yes, it seems that there is an issue with "test membership" button. When I login as different users instead of using test membership all is working. I tried the "switch to user" plugin but that didn't work either. Have a plugin that loops inside a loop seems to cause an issue.