I did not include any providers that require accounts to be setup.
But, I am not sure whether any of the following errors might be due to missing accounts, or licensing requirements:
Krames Staywell: Server IP address could not be found.
Clinical Key: www.elsevier.com refused to connect.
PubMed: pubmed.ncbi.nlm.nih.gov refused to connect.
Sanford Guide: webedition.sanfordguide.com refused to connect.
MicroMedex: Unable to authenticate the user with the provided credentials.
Mayo Clinic: www.mayoclinic.org refused to connect.
NOTE: We are using the Docker container image for all of our deployments and environments.