Hello Fredy,
Looks like there is some issue with ADS and not with the functional configuration.
Run program fp_pdf_test_00 to verify if ADS is running correctly.If you encounter any issues,reach out to Basis or SAP Portal team for assistance
Proxy configuration and adobe services
AdobeDocumentServices ADS failure
Some SAP Notes to refer
SAP Note 1177315 - ADS RFC destination test return 403 404 code
SAP Note 1368090 - Central Note for ADS on NW71
SAP Note 1757467 - Adobe Document Services (ADS) in NW AS ABAP 7.4
Hope it helps
Regards
Sandy