I made a document and the PDF works fine, all the images are there but the document has missing text blocks, There are some texts that do appear but most of them are missing, what could be the cause? I'm using the same font in the texts that do appear so that makes me think is not a font related issue.
There can be several reasons. First, the reader. Is it a browser integrated reader or stand-alone? If stand-alone, is it Acrobat Reader or third party?
Second, the installation of the reader. Will the PDF show the same (bad) way on another PC or tablet?
Third, the PDF itself. Is it standard PDF type or PDF-A/PDF-X? Are the fonts embedded or not? Are there different layers?