Thanks for your inquiry. Please check following documentation link to replace fonts in existing PDF document. You can replace fonts before PDFA conversion. However if the issue persist then please share your source PDF document here, we will look into it and guide you accordingly.
But with this replacement we have to know all the fonts, which causes errors to replace them with a convertible font like ‘Arial’.
The PDFs will uploaded by random users and and then converted to PDF/As, therefore will don’t know all the fonts which could be in the PDF.
Is there any method or something like that, that give us all allowed fonts for using in a PDF/A? Then we can check if the the font is a valid one and if its not, we replace it with a valid one.
The error might be occurring if font is not properly embedded inside PDF file. However please share the resource file, so that we can test the scenario in our environment. We are sorry for this inconvenience.