Rest API Returns Nothing With a Query

Hello,
I currently use an older version of the CRM (7.6) which uses the API 4.1, I’m current accessing the REST API and it works if i want to get all of the entries inside the module “Leads” but as soon as i put anything inside the query paramater it will return nothing.
I’ve tried looking in the logs but never see it come through when there is a query but if it’s blank then it will log.

Has anyone had this trouble before? if so may someone please help me know what im doing wrong.

Which log are you checking? Make sure you check also php_errors.log to see PHP Fatals