PPT to Adobe Tag Reading Order Errors

Hello, I have a ppt document that needs to be accessible to screen readers in PDF. I have tagged the order of my heading, images and text in the order I want it to be read. When I generate the PDF, some text gets left out of the reading order, or the order changes all together. Side note, I have a header and footer tagged as artifacts because I don’t want them read for each page. Any suggestions as to correcting the error?