Solution:
When going live while using DocuSign PHP SDK, set Host parameter to https://eu.docusign.net/restapi
or any other subdomain provided by DocuSign that suits you best (eu, na1 ,na2, etc...).
Explaination:
When working with DocuSign PHP SDK, you don't need to do login request to retrieve baseUrl
parameter for your actual request (ex: creating Envelope). Instead you set Host parameter right at the beginning of your code and don't care about baseUrl
anymore.
And that is where the problem lies. WITHOUT SDK, you first do login request to https://www.docusign.net/restapi/v2/login_information
to get back your baseUrl
paramater (ex: https://eu.docusign.net/restapi/v2/account/1234/envelopes
) and use that for actual request. So when working WITH SDK, set the subdomain of Host parameter to eu, na1, na2 or any other valid value provided by DocuSign right away.
I found the solution thanks to this answer: https://stackoverflow.com/a/44119359/3970975