Troubleshooting Tip: Error: ‎552 5.6.0 Headers too large (32768 max) Reason: [{LED=552 5.6.0 Headers too large (32768 max)};{MSG=}

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Description	This article describes how to troubleshoot a scenario where a Microsoft Office 365 outbound connector shows the following error: '552 5.6.0 Headers too large (32768 max) Reason: [{LED=552 5.6.0 Headers too large (32768 max)};{MSG=}
Scope	FortiMail.
Solution	A Microsoft Office 365 outbound connector shows the following error: Error: ‎552 5.6.0 Headers too large (32768 max) Reason: [{LED=552 5.6.0 Headers too large (32768 max)};{MSG=} Check the Mail Event Log on the FortiMail end. A similar corresponding error will likely be present: Solution:  Navigate to Policy -> IP Policy -> IP Policy -> Policy ID -> Session Profile under the SMTP Limit toggle and increase the header size limit shown under the respective session profile.