I have added an application Page (MyCertificate.aspx) which generates PDF file by using Crystal Reports into an existing SharePoint solution. Everything works fine on my development server but after deploying to Test environment, IE and Chrome did not show any thing, but Firefox throws this error:
XML Parsing Error: no element found Location: https://MyPortal/MyPage/_layouts/15/results/MyCertificate.aspx?spid=ENG&pid=12 Line Number 1, Column 1:
The thing is, its a pretty big solution (which contains many application pages) but everything works fine except the Page:
MyCertificate.aspx and every thing works fine on development server.