inbox api timestamp query returns results before the requested start

[dduran1967]

Example:

// 1555351286000 resolves to 2019-04-15T18:01:26.000Z

GET https://adwerks-dev.rl.hsfaffiliates.com/inbox/?by=timestamp&from=1555351286000

The first message in the result
id: https://adwerks-dev.rl.hsfaffiliates.com/inbox/d03bdf971bb44fdd9a2b94df83820afd

has a timestamp of 1555335479404 which resolves to 2019-04-15T13:37:59.404Z, several hours before the request.