First, review the email account settings and look for any customization of filters that might be interfering with Spam filtering.

1. Check account settings and ensure that the email account is configured for spam filtering.
2. If changes to the spam filters have been made, see if reversing these changes mitigates the issue.
3. Contact the Email service provider to find out if there is a specific announced delay in the spam filter.
4. See if any new updates to the Spam filter have been installed on the system.
5. Check for any known issues that have been reported related to the spam filtering algorithm.
6. If all of the above options have been exhausted, contact a technical support representative who can provide further guidance.