Message blocked because it contains content identified as spam. AS(4810) - PDF issue

I am having the same difficulty as of this morning. I am unable to send any PDFs as attachments as they are being returned as spam. Please update me with any positive news.

Looks like everyone is having the same problem as of a day or two ago. Microsoft must've done something...

I am trying to send a PDF attachment and I keep getting the message that it's been identified as spam. I haven't had this issue until tonight, and PDF attachments worked 24 hours ago. This is happening from multiple recipients: Gmail, Yahoo, .me, etc.

Things I've tried:

Test emails without the attachment (they go through)

Test emails with a different PDF attachment that I sent yesterday (they don't go through)

Test emails with different text in the subject and message body, and with the attachment (they don't go through)

Test emails with the file as a .fdx (Final Draft) rather than PDF (they go through)

Test emails as a One Drive link rather than an attachment (they go through)

Renaming the PDF file (it doesn't go through)

So it appears to be a PDF issue. I'm accessing Outlook on my browser using Chrome on a MacBook Pro. For work purposes I need to be able to send PDF documents as attachments, so I'm hoping to get this figured out soon. I work in a television writer's room so 7 million viewers are depending on me!

Thanks so much for any advice!

IDEM ...... ONLY PROBLEM FOR PDF ATTACH FILE!!!!!!!!!!!!!! SOLVING PLS

Im getting failures using Outlook webmail, havent tested on client. You can zip the file(s) for now as a workaround. Also, Reddit says changing your email formatting from html to text lets a native pdf send, but I have not tested this.

I am having the same issue. Workaround is to change the email type within the email your composing is to change it to plain text format (3 dots to the right of right of the email/select plain text)