Good evening Jennifer and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
We are sorry to hear about the error message you have experienced.
I would love to help you with this topic.
On certain orders, it seems that the download link sent in the email gets corrupted for some reason.
We apologize for the inconvenience caused by this glitch.
We are actively working on a solution for this.
Alas, I cannot guarantee when it will be fixed, as it’s in the development team’s hands now.
They need to assign it, code it, test it, and schedule it for release.
The good news is that you will be contacted as soon as a fix is available.
Thank you for your patience as we see this through.
In the meantime, you can easily work around this by downloading your premium add-on directly from your account at https://theeventscalendar.com/my-account/downloads/
Best regards,
Geoff B.