The issue may occur in any of the following instances:

• The email violates an existing TMEMS - Inbound Protection policy
• The Email Reputation Services explicitly rejected the IP of the sending mail server
• The mail is being sent to an invalid recipient
• The IP/domain name of the sending mail server is on the blacklist of another filtering software/service that the receiving domain is using
• The mail violates a policy of another filtering software/service used by the receiving domain

To resolve the issue:

1. Check existing TMEMS - Inbound Filtering policies that the email may have violated. The default global settings are as follows:
   • Message size limit:  TMEMS: 150 MB per message
   • Recipient limit: 1000 addresses
   • Total embedded layers within a compressed file: 20 layers
   • Total decompressed message size: 60 MB
   • Total files in a compressed archive: 353 files

2. Check the mail tracking logs of TMEMS.

   1. Log on to the TMEMS - Inbound Filtering console.
   2. Go to Logs > Mail Tracking.
   3. Select the date range and other filters as needed.
   4. Specify the sender of the missing email.

   5. Check if the sender is listed in the Accepted Traffic or the Blocked Traffic tab, and do one of the following:

      • If it is listed under Accepted Traffic, proceed to Step 3.
      • If it is listed under Blocked Traffic and you are sure the sender can be trusted, you can opt to add it to the Approved Senders list.
        • For TMEMS:
        1. Login to TMEMS console.
        2. Go to Inbound Protection > Connection Filtering > Sender Filter > Approved Senders.
        3. Click Add.
        4. Enter the email address of the sender, then click Add to List.
3. Make sure that the recipient of the email being sent is valid.
4. Check the IP of your mail server using the MAPS - Support - Lookup Tool to see if your IP is being blocked by the receiving domain.
5. Contact the receiving domain and see if they have any policy restrictions or blacklists that may be causing the bounced emails.