odata model contains error

Hi All,

I have created one Service in ECC System it is working fine in Development and Quality System but now i am facing an issue in production system with the below following error.

service       :     sap/opu/odata/sap/ZTEN_APR_SRV/$metadata

<errorxmlns="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">

</error>

please let me know how to resolve it