surveymonkey api increment data

Hello,

Not sure if this is a right platform to ask this question - nevertheless thought of getting some inputs.

I ran into a problem fetching the data on PBI desktop from SurveyMonkey API with the URL below - the API call works fine without the start_modified_at parameter.

https://api.surveymonkey.net/v3/surveys/" & SurveyId & "/responses/bulk?start_modified_at=2018-01-01page=1&per_page=100

Error - DataSource.Error: Web.Contents failed to get contents from 'https://api.surveymonkey.net/v3/surveys/87662822/responses/bulk?start_modified_at=2018-01-01page=1&per_page=100' (400): Bad Request

Please suggest.

Thanks,

Ajay