If this forum is not in depth-enough you could try the mailinglists (for community support).
The idea to understand dirmngr and gnupg is to get the diagnostic messages turned up
and then look carefully.
(This famos elder X509 guide shows why debugging CMS and PKIs is so hard: https://www.cs.auckland.ac.nz/~pgut001/pubs/x509guide.txt 
)
For completeness: If you seek paid support because you are trying get a large installation
with many seat rolling, look at https://www.gpg4win.de/support.html
Best Regards,
Bernhard