Thanks for the quick reply, @johan.
The specific error is: “No Solution Stack named ‘64bit Amazon Linux 2018.03 v2.10.0 running Go 1.11.5’ found. (Service: AWSElasticBeanstalk; Status Code: 400; Error Code: InvalidParameterValue; Request ID: …”
It does show CREATE_COMPLETE for AWS::ElasticBeanstalk::Application. But then the configuration fails.
In case it matters, I’m using us-east (DC).