Although they're meant to be supported, MH won't let me upload DOCX, XLSX or even DOC files to my Library as Attachments. I can see that a message starting "Ooops" appears on screen but it flashes away too quick to read.

I've also tried uploading the files while I'm creating an email in a Journey but they won't uplaod there either.

I've tried Chrome and Edge. Same result.

I've attached the files.

How do I get them uploaded?

Many thanks

Steve