Why I Cant Check My Case Status In Uscis?

Why I Cant Check My Case Status In Uscis? Please check your receipt number and try again. If you need further assistance, please call the USCIS Contact Center at 1-800-375-5283. If you are still not able to check your case status, it is a good idea to call the USCIS number mentioned (1-800-375-5283) and check