Exchange Server SE - we can only receive 20MB per mail but everything shows 150MB

Hi @ReneDoettl,

Welcome to Microsoft Q&A, and thank you very much for reaching out to us.

Please note that as a forum moderator, I don’t have access to your specific configuration, and my testing environment is limited. However, I’ll do my best to assist you using available documentation and research.

Based on your description, could you clarify whether the email in question is coming from the internet or through authenticated SMTP submission from internal devices or users? Also, do you have one connector or multiple connectors configured?

In the meantime, since you’ve already checked the organization‑wide and mailbox limits, please also run the following to see if any transport rules are enforcing lower size thresholds:

Get-TransportRule | Where {($_.MessageSizeOver -ne $null) -or ($_.AttachmentSizeOver -ne $null)} | Format-Table Name, MessageSizeOver, AttachmentSizeOver

Additionally, you can list the limits configured on all user mailboxes to spot any outliers quickly:

$mb= Get-Mailbox -ResultSize unlimited; $mb | where {$_.RecipientTypeDetails -eq 'UserMailbox'} | Format-Table Name,MaxReceiveSize,MaxSendSize,RecipientLimits

If possible, please share the results or a screenshot of the output via private message.

Looking forward to your response.

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For messages to and from the internet its important the the org wide receive and send limits match.

Get-TransportConfig | Format-List MaxReceiveSize,MaxSendSize

Make sure both of these are set to 150MB.