Hello Saurabh,
did you only grant select access or did you grant select access with grant option._SYS_REPO needs select access rights with grant option to grant the select privilege to your user.
For more details please have a look to the documentation (Required Permissions - SAP HANA Modeling Guide - SAP Library) or use the search function here to find the other questions already answered to that topic.
Regards,
Florian