Hi there. In this case, the general, publicly available API endpoints should be api.clockify.me rather than developer.clockify.me, which should be the dev stage.
Could you please update the GET method, and let us know if it works as expected?
Error:
“You entered invalid value for field : [end]. Values that represent [end] can’t be null and can’t be empty. Please make sure that the [end] date is not greater than 9999-12-31 and not less than 0001-01-01. Ensure that the [end] date is in following format: "yyyy-MM-ddThh:mm:ssZ" Example: 2018-11-29T13:00:46Z.”,“code”:501