Again I had to create a new question because i still get an "Unexpected error" when I try to answer. (By the way I tried all suggestions to fix the error and also reinstalled Firefox but still have the error) jscher2000 i think you are correct. The blue link in the PDF file is not a web link but a link to the specific attachment. It appears browsers are currently unable (not programmed) to access attachments directly. I tried in MS Edge with the same result. After contacting MS Support, MS stated that they are aware of the issue and that they are working to fix it in a future release of Edge. Attachments can be accesses in Adobe Acrobat as you described, but it would be good to be able to access them directly from Firefox instead of having to save them and then using Acrobat.