Good evening Rebekah and welcome back!
Thank you for reaching out to us.
We are sorry to hear about the 404 error messages you have been receiving.
I would love to help you with this topic.
My first recommendation would be to update both the Events Calendar and the Events Calendar Pro to their latest versions.
Secondly, please go through the following guide: https://theeventscalendar.com/knowledgebase/fixing-http-404-errors/
Finally, please make sure you empty Site Ground’s cache.
Let me know how that goes.
Best regards,
Geoff B.