Microsoft Graph - Filter Start/DateTime

Working with the nodejs library for Microsoft Graph, trying to query my calendar and return the next 5 events.

Query setup:

client
        .api('/me/events')
        .header('X-AnchorMailbox', email)
        .top(5)
        .filter('Start/DateTime ge 2017-05-26T00:00:00')
        .select('subject,start,end')
        .orderby('start/dateTime DESC')

When executed Graph replies with:

"code":"BadRequest","message":"The DateTimeOffset text '2017-05-26T00:00:00.000' should be in format 'yyyy-mm-ddThh:mm:ss('.'s+)?(zzzzzz)?' and each field value is within valid range."

Does 2017-05-26T00:00:00 not match 'yyyy-mm-ddThh:mm:ss('.'s+)?(zzzzzz)?'?

via Oliver