User(s) can't receive emails to site inbox
From CashCrusaderWiki
If a user can't receive emails to the site inbox first check the following:
- Is the user's "Send emails to:" setting "Site Inbox" or "Site Inbox & Email".
- Was the email you sent targetted to group(s) other than to which the user belongs to? You can check this by going to "Send Mail", click on "copy" on the right side of the email, scroll down to the bottom of the page and check the targetting settings.
If the above settings are correct and the user is still unable to receive emails to the site inbox repair your database. This is commonly done through your hosting control panel or phpMyAdmin. If you are unsure how to repair the database please contact your host for assistance.