What version of Tableau Server are you trying to publish to? See the versions as they relate to the Rest API here - Versions-Tableau Server REST API
Are you utilizing 10.0 Tableau Server?
Our server is on 10.0.2 (10000.16.1004.1720) 64-bit and I was trying to publish the data source using API version 2.3. Do we have any known issue related to such publish? I think I saw a known issue which is similar to this but related to publishing workbooks. I can't find this known issue any more.