Signing an APP for Mac (not Xcode, Python compiled)

Hi,

I'm trying to sign an App (original python compiled for MAC) and the codesign process is failing with error:

The command from terminal that produced the error was:

codesign --sign "$devID" $file2sign

Warning: unable to build chain to self-signed root for signer "Apple Development: ..." errSecInternalComponent

I have both a dev certificate (current, just downloaded a couple of days ago) and the intermediate certificates.

When I run the command

security find-identity -v -p codesigning

I can perfectly see my dev cert, but only listed as "valid identities" nothing is listed as "matching identities"

Any help will be highly appreciated!