Hi there,
Thank you for reaching out to us!
Could you please confirm that both The Events Calendar and Events Calendar PRO are up to date? The latest versions are 4.6.9 and 4.4.21. The permalink logic for recurring events was moved from The Events Calendar to Events Calendar PRO on version 4.4.14, so it could be the cause of the issue you are experiencing. You can download the latest version here.
After that, 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). Be sure to clear your site cache and browser cache after this change.
Does it help you to solve the problem? If the issue persists, please let me know and I’ll be happy to help you with the next steps.
Cheers,
Patricia