Google Docs in attachment block

I'm getting an error message that just says ERROR with no details when I try to attach a Google doc in the File Attachment block.

From what I can find, there aren't limitations on the file types that can be added as attachments, so I'm wondering why this isn't working or if I'm doing something wrong? The file I'm trying to attach is in a folder available across our entire organization, but not publicly visible.

Thank you.