How to use OData Date filter query to filter data from OData NetWeaver Gateway Service?

Hello,

I am trying to use the OData Filter query. to filter data records from the OData Service, using Date range for filters.

Please check the below URL for the SAP's sample OData Service, with filter option.

Service Query URL :

https://sapes1.sapdevcenter.com/sap/opu/odata/sap/ZGWSAMPLE_SRV/SalesOrderCollection?$filter=CreatedAt eq DateTime

It gives out following error :->

<messagexml:lang="en">'$filter ' is not a valid system query option</message>

Please let me know, if there is any mistake in the Query or is there anything that needs to be done on the
Backend  Service.

Thanks & Regards,

Suraj Kumar