Hi,
if "_SYS_REPO" user doesn't have "select" privilege on your schema, you will get this error while validation of view.
Please fallow below procedure:
1. go to security node of your HANA DB-->user-->
2. click on _SYS_REPO user
3. go to object Privilege tab
4. add either your schema or table then provide select privilege on it.
now try to validate your view again. Validation will go through now.
regards,
sai Krishna.