Error Data Size Limit Exceeded during email submission


Article ID: 170190


Updated On:


Email Email Threat Detection and Response


One or more users are unable to submit false negative emails using the Outlook email submission add-in.



The Outlook submission add-in sends a request to Exchange Web Services (EWS) to get the base64 encoded email content. However, if the EWS response is greater than 1 Megabyte, the email content would not be retrieved due to the size limitation.

The size limit applies to Exchange 2013, 2016 on-prem solutions. There is no limit when submitting on a hybrid environment with Office 365, standalone Office 365 or Exchange Online.

For more information about these type of EWS errors, see EWS Response Codes.


  • Email
  • Outlook Email Submission add-in
  • Exchange 2013
  • Exchange 2016


If the false negative emails cannot be submitted using the Outlook email submission add-in, these emails would need to be reported manually.

Submit false positives for legitimate email flagged as spam

Submit false negatives for email not flagged as a threat