Using magento 2.3.3. I get this error when I delete customers.
Could not rebuild index for empty products array
@Sheba not able to see the screenshot as it is visible once moderator approves it.
@Sheba Have you checked your logs and try to run the below command from root of your directory.
php bin/magento indexer:reindex
there should be 2 reasons
-> Ordered products by these customers is not available in Magento now
-> Reviews shared for those products which are not available now
please cross check it.