timeStamp not working in Sales search via php

I am trying to load all sales for a specific date (ie 1/14/2021). The following code was produced by Postman and works in postman, however in my php script it does not.
I have tried the following:
$tokenURL = "https://api.lightspeedapp.com/API/Account/{$accountID}/Sale?load_relations={$relations}&timeStamp>,2021-01-14";
and
$tokenURL = "https://api.lightspeedapp.com/API/Account/{$accountID}/Sale?load_relations={$relations}&timeStamp>,2021-01-14T00:00:01-8:00";
and
$tokenURL = "https://api.lightspeedapp.com/API/Account/{$accountID}/Sale?load_relations={$relations}&timeStamp>,2021-01-14T08:00:00";
and even converted the date to a datetime object.
However, I am getting records back with the following dates: 2020-02-07T22:35:31+00:00 and beyond..
Any suggestions?