I am using Jira Data Center. I've created this automation and according to other questions I've read it should work, but I am getting an error each time I create a new issue. I previously tried choosing the Epic Link field in the dropdown, which also had this error, so I switched to the Advanced JSON since I saw that others had success with that.
The rule is limited to a single project, the one containing the referenced Epic. The Epic Link field is present on both the Create and Edit screens for the issue type.

