Apologies for the late reply on your question.
May we know if you are still having errors connecting your Basecamp3 connector with Workato?
We already updated our HTTP connector for Oauth2 Authentication type. See screenshot below:
Please also refer to Basecamp3 API documentation here: https://github.com/basecamp/bc3-api
Send us a ticket, we will try our best to assist you with your problem
Workato & Basecamp 3
I am trying to use HTTP w/ Oauth2 to pull a lis of projects from Basecamp3 API. Everything seems right and it generates a popup where I confirm access and it then sends back the callback URL and Workato indicates there was a "Server Error"