Follow this guide if you want to prevent users from enrolling in more than one scheduled event based on a topic.
Make sure you have the app SharePoint|sapiens Modern User Interface version 184.108.40.206 or higher installed. After installing the new version, open the Site Contents view on your SharePoint site, click on the app SharePoint|sapiens Event Management, click on Change Settings and save the settings again.
Add the column ‘Max. Enrollments per User’ to the topic form
If you want to prevent users from enrolling in more than one event, add the column Max. Enrollments per User to the Topic content type in the list Training Catalog. Open the list settings, click on Topic in the content type section, click on Add from existing site or list columns and add the column Max. Enrollments per User.
Create or update a topic
If you now create or modify a topic, you can enter the maximum number of events users can enroll in that are based on this topic. If you want to prevent users from enrolling in multiple events, enter 1. If you don’t want to limit the number of events user can enroll in, leave the column empty.
I hope you found this guide useful. If you have any questions, please send an e-mail to email@example.com.