I have the same issue, vscode tells me what the issue is, just not how to solve it:
Power BI is Following Standards:
What Power BI Receives:
{"@odata.context":"...","value":[...]}{"error":{"code":"500","message":"..."}}
This is invalid JSON - it has two root objects. Power BI correctly rejects it.
Other Tools Would Fail Too:
The Server Should Return:
Success Case:
{
"@odata.context": "...",
"value": [
{
"UUID": "...",
"TotalEnds": 3730,
"Event": {
"UUID": "...",
"EventName": "..."
}
}
]
}
Error Case:
{
"error": {
"code": "500",
"message": "Exception occurred while processing OData request."
}
}
NEVER Both:
The server is mixing success and error responses, which violates all standards.
Power BI's Response is Professional:
Power BI gives you a clear, accurate error message:
"Invalid JSON. More than one value was found at the root"
This is exactly what should happen when receiving malformed JSON.
Bottom Line: Power BI is doing its job correctly. The OData service needs to be fixed by whoever maintains it (likely your Mendix team or backend developers).