400 (Bad Request) after changing parameters or taking over a dataset.

Hi,

When changing parameter in the PowerBI Service we see a 400 (Bad Request) error popup in the console. When checking Network traffic we see that the API call to https://wabi-north-europe-redirect.analysis.windows.net/V1.0/myorg/datasets/67fae1d5-c85c-44b0-8627-863ecd6b2ead/Default.UpdateParameters responds with the 400 error with the following response: "error":{"code":"DMTS_UnsupportedConnectionStringError","pbi.error":{"code":"DMTS_UnsupportedConnectionStringError","parameters":{},"details":[],"exceptionCulprit":1}}}

This same response is sent back when we try to take over a dataset/report, this also results in a 400 Bad Request error.