Configure PayPal enrolment This is already done in prototype 3.3. If you will use this site to test the issue you can skip this section. Login in Moodle web as admin and go to Site administration > Plugins > Enrolments > Manage enrol plugins. Click the eye next to PayPal to enable it. Click "Settings" next to PayPal. In there, introduce a valid "PayPal business email". Now go to Site administration > Courses > Manage courses and categories and create a new course. Don't enrol anyone in the course. Go to the course and go to "Enrolment methods". To do so in Boost, you need to click the Gear icon in the course and select "More...". In there, select the "Users" tab and click in "Enrolment methods". In the "Add method" select, pick PayPal. Configure the instance name and the cost (it cannot be 0, I suggest you to use 0.01). Test the issue Install the app in an Android/iOS device or use Moodle Desktop. Login in the app as a student. In My Courses or Course Overview, click on the top right icon (magnifying glass) to search courses. Search the course with PayPal enrolment (in proto 3.3, search "PayPal"). Check that you see the PayPal icon at the right of the course. Click on the course. Check that you see a message saying that PayPal is enabled and there is a button to pay with PayPal. Click the button. Check that InAppBrowser is opened with the course (you might have to login first). Proceed with the PayPal enrolment in the InAppBrowser until it's done. In Android/iOS device, the InAppBrowser should be closed automatically once you reach the course contents after enrolling. In MoodleDesktop it might not be closed automatically, so you might have to close it yourself when you reach the course contents. After InAppbrowser is closed, check that the app data is refreshed and now you see the course options: contents, participants, etc.