Exchange - Messages encoding error

Question

Hi There,
I have an external sender disclaimer message defined to my exchange users.
This message is an HTML format code that is injected into the received message when the external to organization sender is verified.
Some messages, mainly newsletters, are received with mismatched characters.
After some investigations, I verify that some newsletters are predifined with charset UTF-8 encoding, and on this case, when message arrives from an external source, Exhange add the predifined warning message, and then encoding message with iso-8859-1. Once the message is injected, the original encoding UTF-8 is changed to iso-8859-, and a mismatch cahrset occours.
In resume, at the end of this proccess, messages with original encoding UTF-8, they get mismach charateres, once the warning message is injected by Exchange and re-encode the original email with iso-8859-1.

Does anyone with a similar error?

Answer 1

Hi @Marco Costa ,

I've seen a similar issue which was finally resoved by adding the key <add key="DisableDetectEncodingFromMetaTag" value="true" /> to the EdgeTransport.exe.config on each mailbox server:

1. Back up the EdgeTransport.exe.config file on each Exchange server, which is located in the following path by default:
   C:\Program Files\Microsoft\Exchange Server\V15\Bin
   
2. Stop the transport service (MSExchangeTransport ), and then open the EdgeTransport.exe.config file with Notepad, add the entry below to the <appSettings> section (you can add it in the line before "</appSettings>"): <add key="DisableDetectEncodingFromMetaTag" value="true" />
   
3. Save the file, and then restart the transport service (MSExchangeTransport).

Based on my understanding, this issue usually occurs because the character encoding in the META tag of this type of mail is different from the character encoding in the MIME part, and the Exchange server re-encodes the mail when it adds the HTML disclaimer, this may lead to garbled characters as encoding in the META tag will be read incorrectly.

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