dear developers;
kindly provide option to add referer manually or if a link is missing referer then convert its url to referer.
it will solve error 403 in many sites.

thank you

You have to provide links for others to verify the issue and usually 403 is from the site not from FDM and some sites don't permit FDM type downloads.

https://en.wikipedia.org/wiki/HTTP_403

darkseid wrote: if a link is missing referrer

Referrer is missing when you copy and paste link directly into FDM rather than allow FDM to catch download link AND REFERRER from the download page.
It's user fault.

dear friends;
it is not always same that fdm catches the download from web pages but sometime user has to give custom url for download. So, if the add download dialog have useragent (default) and referer textbox to add then the error 403 will not be there during analyzing link and download.
OR
if a download is missing referer then automatically the url/host became its referer during download so the 403 error will not be there.
I have tried in my codes and it worked fine.
thanking you

Adding url and downloading working fine with fdm 3.9
But showing error 403 in fdm 6.17. dear developer kindly implement same protocol as fdm 3.9.

Thanking you

Could you provide such links, please? Stop ignoring the reporting rules.