Unable to fill pdf form

Hi,
please check if your annot is null..
Can you reproduce the issue with the demo version? If yes please send us the pdf so we can check it..

The annot is not null. It happens with every pdf I try but, anyway, I have attached one of them. I have a premium license and also I have checked file write permissions.

Boolean canBeWriten= ficheroDestino.canWrite(); <- This returns true.

But when I get the permissions with your library:

int permission = m_doc.GetPermission(); <- This returns -1