Dear Doug_726,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
I understand that you have a concern regarding Attack Simulation Training not e-mailing all users.
For now I may not have root cause why targeted users are excluded from emails but you could help by running a message trace for the second simulation and also specify the one employee who received it.
Regarding the extended message trace you can send to me via private message using this link Message trace.
Please find this for your reference on running message trace: https://docs.microsoft.com/en-us/exchange/monitoring/trace-an-email-message/run-a-message-trace-and-view-results
We look forward to your response. Thanks for your cooperation.
Sincerely,
Anesu | Microsoft Community Moderator
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