Emails are not added to Salesforce using Email to Salesforce (E2S) service
|Knowledge Article Number||000004032|
Emails are not associated with the Salesforce record when using the Salesforce for Outlook plugin or Email to Salesforce.There is also no bounce back email that is sent when this occurs.
When sending emails to a record in Salesforce (BCC' ing the Email-to-Salesforce address), the emails are NOT being associated and displayed under the Activity History section of that record nor in the Unresolved Items
CAUSEMost probably the Advanced Email Security Settings is enabled in their org and the users’ email server does not support any one of the following protocols:
SPF, Sender ID, or DomainKeys.
For Salesforce to accept an e-mail with this feature turned on, means your users’ email server has to support at least one of the following protocols: SPF, Sender ID, or Domain Keys.
1- Log in to Salesforce as an administrator and navigate to Setup | Email Administration | Email to Salesforce
2. Click on Edit
3. Uncheck the box for Advanced Email Security Settings
4. Click on Save
After this change, try to reproduce the issue and confirm that it has been added to a Salesforce record or the unresolved items queue