Cant open pdfs in my emails

Are you downloading the PDFs directly to your phone?

I don't think they will open up automatically in the Acrobat Reader mobile app  you just tap on the email attachments.

This happens with OneDrve files too. You can't tap directly on that PDF or it will open in whatever PDF viewer Micrososft supports, not Acrobat Reader mobile.

Make sure that you physically download the PDF attachment to your mobile device, then try opening them with the Acrobat Reader mobile app.