It is not possible to sign a PDF document which contains a form.
There is no exception traces.
Please find attached 8 documents :
- A document with a visual signature form (does not work) (Doc1)
- A probably latex generated document (does not work) (Doc2)
- A document with an annotation (does not work) (Doc3WithAnnot)
- And the same document without annotation ( which works well ) (Doc3WithoutAnnot)
- And their signed release.