Exchange Server 2016 Hybrid EXO Throttling

Hey @Xintao Qiao-MSFT , thank you for your answer, but it is not helpful, because all my servers are up to date. As described the header information itself is outdated on one of them. The installed Version and Build Number are all the same:

[PS] C:\Windows\system32>Get-ExchangeServer | ft Name,Edition,AdminDisplayVersion

Name Edition AdminDisplayVersion

             Enterprise Version 15.1 (Build 2507.17)

             Enterprise Version 15.1 (Build 2507.17)

             Enterprise Version 15.1 (Build 2507.17)

             Coexistence Version 15.1 (Build 2507.17)

[PS] C:\Windows\system32>$ExchangeServers = Get-ExchangeServer | Sort-Object Name

[PS] C:\Windows\system32>ForEach ($Server in $ExchangeServers) {

Invoke-Command -ComputerName $Server.Name -ScriptBlock { Get-Command Exsetup.exe | ForEach-Object { $_.FileversionInfo } }

}

ProductVersion FileVersion FileName PSComputerName

15.01.2507.039 15.01.2507.039 D:\Program Files\Microsoft\Exchange Server\V15\bin\ExSetup.exe

15.01.2507.039 15.01.2507.039 D:\Program Files\Microsoft\Exchange Server\V15\bin\ExSetup.exe

15.01.2507.039 15.01.2507.039 D:\Program Files\Microsoft\Exchange Server\V15\bin\ExSetup.exe

15.01.2507.039 15.01.2507.039 D:\Program Files\Microsoft\Exchange Server\V15\bin\ExSetup.exe

Hi, @Steve_1337

1.When a custom message ID is overwritten by the SMTP server's message ID, the SMTP server may change the message ID, which causes mail threading and recognition issues. Verify that the SMTP server information is correctly configured, such as the server name and port.

2.Are you running unsupported software on your server, which also causes Microsoft to increase the limit and block the mail.

3.If possible, migrate servers to the cloud as early as possible to avoid certain issues.

4.Based on the information I found, older versions of Exchange, such as Exchange 2016 CU8, may have some known issues that have been fixed in subsequent updates. It's important to make sure your Exchange servers are running the latest cumulative updates (CUs) to avoid such issues.

More information can be found Microsoft's Plan to Block Old Exchange Servers | Practical365

5.You can also open a support ticket with Microsoft for a more in-depth investigation.

Global Customer Service phone numbers - Microsoft Support

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