Hi @SWETHAPRIYA 

1. You can check below link for your LU in ‘Custom Field’ window. I don’t have a link there as I don’t have any objects for this LU. But you will see some link. Click on that and check the status. Keep a screenshot of the original and try doing changes there to see if you get the error still. Or if you have some other similar environment which this custom object is already published, you can compare the ‘Approved Detail Views’ settings with that.

2. Check if you see invalid database objects. If yes, fix them and see if it’s working.
3. You can also try Refreshing the server Cache. 

Thanks,

Imanka.