Connection to Power Bi

We are trying to implement the use of Power BI Dashboards within or business. I am connecting Power Bi to our Nav Database via an OData connection. The connection works fine and data comes through as expected, no worries here. However If I log into Navision or have it open (Have a connection) i get the following Error When I try and do anything essentially, i.e refresh, Modify Queries etc.

DataSource.Error: Microsoft.Mashup.Engine1.Library.Resources.HttpResource: Request failed:
OData Version: 3 and 4, Error: The remote server returned an error: (400) Bad Request. (Bad Request)
OData Version: 4, Error: The remote server returned an error: (400) Bad Request. (Bad Request)
OData Version: 3, Error: The remote server returned an error: (400) Bad Request. (Bad Request)
Details:
DataSourceKind=OData
DataSourcePath= (This would be my OData Path)
Any ideas will be appreciated.