Hey Emma,
Thank you for reaching out to us!
Can you please make sure that The Events Calendar and Events Calendar PRO are both up-to-date?
After the plugin update, please access your Dashboard and head over to Settings -> Permalinks for a permalink flush (no need to change anything, just visit the permalinks page: WordPress will automatically flush your permalinks once you visit it).
Don’t forget to clear your site’s cache and your browser cache after this change.
I hope this helps! If you need anything else in the mean time, please let me know and I’ll be happy to assist!
Regards,
Patricia