Rally emails missing for some users

Products

• Rally SaaS
• Rally On-Premise

Issue/Introduction

We have had several users report that are no longer receiving emails from Rally.  

We @mentioned users in a Feature and neither received an email.

We have confirmed that the users have email enabled and they do not have any rules setup.  Is it possible to see if the emails were sent?   

Resolution

Please open a support ticket and include the Rally userid of the user with the issue so we can assist you with this.

Additional Information

Other possible issues are if their email server is throttling their emails. You may see errors like the ones below:

Email was deferred due to the following reason(s): [IPs were throttled by recipient server]

and:

450 too many connections from your IP (rate controlled)