The connection fails before any answer
Check the address, the trust file and your credential files. An expired credential can end the connection before the AIDC Server answers. Ask for a new credential; never turn off certificate checks to make the error disappear.
The AIDC Server answers 403 Forbidden
Your identity is valid but lacks the permission for this operation, or the account is no longer accepted. Ask the administrator which permission is missing before requesting a new one.
The AIDC Server answers 503 on a protected request
The AIDC Server could not confirm your access at that moment. This is not a problem with your credential: retry after a short while and report a lasting failure with the time and the exact status.
A package is reported as not found
List the packages for the tool and compare the tool, version, distribution, platform and architecture. A missing value is not a wildcard, and an entry from a vendor does not prove that the AIDC Server holds the archive.
A version query fails while downloads still work
Version discovery can depend on a vendor you cannot reach. Use package coordinates you already know, or the list of packages published on the AIDC Server.
An upload is rejected as invalid or as already present
Use the archive and manifest exactly as your packaging workflow produced them. If the package already exists, compare its checksum with yours; an earlier attempt may have succeeded even if its answer was lost.
What you getA concrete next step for the failing request, with the exact status and package you were using.