X-Reply-To header not changing Reply-To in Microsoft Graph API

Question

X-Reply-To header not changing Reply-To in Microsoft Graph API

DJ-MoMo 0

Here is what I'm doing in my API call:

Creating a Message object

Setting the X-Reply-To header to my custom email:


**message.Headers.Add("X-Reply-To", "******@email.com");**

Sending the email via the Graph API

When looking at the full headers of the sent message, I can see the X-Reply-To field populated correctly. But the Reply-To remains unchanged.

I expected that setting X-Reply-To would override or change the Reply-To field as well, but that doesn't seem to be the case.

Is there something else I need to do to get X-Reply-To to actually modify Reply-To when sending through the Graph API? Or is this not possible and I have to find another approach?

Any help or insights appreciated! I'm using Microsoft 365 with the latest Graph API.

SokiGuo-MSFT 31,766 Reputation points Microsoft External Staff

2023-11-01T07:42:42.5566667+00:00

Hi @DJ-MoMo

Just checking in to see if above information was helpful. If you have any further updates on this issue, please feel free to post back. If you think my reply is helpful to you, please remember to mark it as an answer. Warm thanks.
DJ-MoMo 0 Reputation points

2023-11-01T11:51:42.38+00:00

@SokiGuo-MSFT , No that did not answer my question. See my follow up comment.

2 answers

Your answer

SokiGuo-MSFT 31,766 Reputation points Microsoft External Staff

2023-11-01T07:42:42.5566667+00:00

Hi @DJ-MoMo

Just checking in to see if above information was helpful. If you have any further updates on this issue, please feel free to post back. If you think my reply is helpful to you, please remember to mark it as an answer. Warm thanks.
DJ-MoMo 0 Reputation points

2023-11-01T11:51:42.38+00:00

@SokiGuo-MSFT , No that did not answer my question. See my follow up comment.

Answer 1

Glen Scales 4,376

The replyTo property is strongly typed in the Graph so you just need to use that property in you request eg

{
    "message": {
        "subject": "Meet for lunch?",
        "body": {
            "contentType": "Text",
            "content": "The new cafeteria is open."
        },
        "toRecipients": [
            {
                "emailAddress": {
                    "address": "******@domain.com"
                }
            }
        ],
        "replyTo": [
            {
                "emailAddress": {
                    "address": "******@domain.com"
                }
            }
        ]
    }
}

DJ-MoMo 0 Reputation points

2023-11-01T11:50:36.4+00:00

@Glen Scales , Thank you for your comment. The ReplyTo does get added to the email by adding "x-Reply-To"through Microsoft Graph API. And I can view the email head and see x-Reply-To: ******@domain.com but the Reply-To, shows ******@domain.com

The problem is that it is not changing the ReplyTo to reflect the address added. It still maintains the sender’s address.

Does this make sense?
Glen Scales 4,376 Reputation points

2023-11-01T23:44:13.2366667+00:00

Not sure I've understood you correctly but using your method message.Headers.Add("X-Reply-To", "****@email.com");** won't work because when you send an email via the Graph (or any of the Exchange API's EWS or Mapi) the Exchange store won't process that header as part it's submission process (SMTP which is a different submission process may process it but even then i don't think it will). When you send an Email using any of the Exchange store submission endpoints it uses TNEF (Transport Neutral encapsulation format) then the message gets converted to Mime in Transport Pipeline so using that strongly typed property is important have you tried this ? I know that works as I've used it. You can use the extended properties to do it as well which is a lot more complicated there is an EWS example https://stackoverflow.com/questions/35988918/set-reply-to-address-in-outgoing-email-ews which would also work in the Graph but they have made this process a lot easier by now providing the strongly typed property.

Answer 2

LaserGecko 0

The ReplyTo does get added to the email by adding "x-Reply-To"through Microsoft Graph API.

@DJ-MoMo That is incorrect. That header is sent by MS Graph, but it is not set by you as a header. As of July 8, 2024, only custom headers are supported.

replyTo is sent in the payload since, just like "body", "subject", and "toRecipients", it is a property of the message resource.

If the address is not changed after being sent correctly, it's either an MS Graph error or an Entra authorization issue.

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