Hello @JimA655 ,
Library imports have a maximum size of 5mb. 5452 KB = 5.452 MB, which would mean the file is too large to be uploaded. You'd either need to reduce the file size, or host it elsewhere and link to it in the email.
If you're trying to import a contact file, the maximum size is 2MB, so you'd definitely need to reduce your file's size for that. Check this article for additional info and tips on formatting contact files prior to import.
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