You may see some of the email activities are not processed in your workflow jobs, if you open any of email activity which contains invalid email addresses; you will see this error message “The Sender, or one or more recipients, could not be resolved to a record in Microsoft Dynamics CRM.”
You need to create a valid Account/ Contact/ Lead/ Queue/ User or Facility/Equipment record with email address mentioned in E-mail activity.
You can set this to create a Contact/Lead automatically, if Sender Email Id is not recognized by CRM
Step 1: Log on to CRM 2011 with administrative account (i.e. the account that was used to install CRM 2011 and CRM 2011 email router)
Step 2: go to File -> Options, this should open up Set Personal option page
If your CRM server to send emails to email addresses which does not belong to any of CRM records this issue could be resolved. You can check this setting as mentioned below.
If you are the system administrator, navigate to Settings -> System -> Administration and click on System Settings and then select E-mail tab and go to section “Set E-mail form options” and allow messages with unresolved e-mail recipients to be sent.