Prismic import stuck at checking

I tried to import a single test document. It's a small document with no media fields, but the importer has been stuck at "Checking..." for over thirty minutes now.

This is really blocking me from testing new import formats. Is there some kind of tool to validate my imports other than the importer itself?

Check out the import documentation to see information about the correct format and structure required for importing documents, which can help you prevent errors and save time during the importing process.