Hello A.S.
Sorry to hear you are having issues with your order statuses in OpenCart. With such a vague question, we are not able to assist. We would need to know the exact steps you are taking to get the error so we can try and duplicate on a test environment. We also would need to know any specific error messages you were getting, when the error began, what exactly you did prior to the error beginning, any extensions you have enabled, what version of OpenCart you are using, is the error for all orders or only specific ones, did you test with both old and new orders, and any other specific details relating to the issue.
Kindest Regards,
Scott M