Currently using Microsoft Graph, wanted to know whether a mail is soft bounced or not

Question

Hi Team,

Here is endpoint in Question : https://learn.microsoft.com/en-us/graph/api/message-get?view=graph-rest-1.0&tabs=http

How do I know whether a message, which we fetch via the get message endpoint above, is indicating a soft bounce or not?

Currently even if we fetch the MIME content, its not giving any data about soft bounce

Please let us know

Answer 1

Hi @sarath

There is no way to check if a message is a soft bounce with a simple API call. You need to use graph SDK to make some logical judgments.

Please refer to the following steps:

• Call the /messages endpoint with the id of the mail you want to check.
• In the response, look for the internetMessageHeaders property, which contains an array of key-value pairs that represent the email headers.
• Loop through the internetMessageHeaders array and look for the header named "X-Microsoft-Antispam-Mailbox-Delivery".
• The value of this header contains a string that indicates the delivery status of the mail. For example, if the value is "noattr:0", it means that the mail was delivered successfully. If the value is "noattr:1", it means that the mail was soft bounced.
• A soft bounce occurs when the mail is temporarily rejected by the recipient's server due to reasons such as mailbox full, server down, or rate limit exceeded. A hard bounce occurs when the mail is permanently rejected by the recipient's server due to reasons such as invalid address, domain not found, or blocked sender.
• You can also look for other headers that indicate the reason for the bounce, such as "X-Forefront-Antispam-Report" or "X-Microsoft-Exchange-Diagnostics".

Here is an example of a C# code snippet that uses Microsoft Graph SDK to check whether a mail is soft bounced or not:

var message = await graphClient.Users["{user id}"].Messages["{message id}"].GetAsync((requestConfiguration) =>
{
    requestConfiguration.QueryParameters.Select = new string[] { "internetMessageHeaders" };
});

bool isSoftBounced = false;
string bounceReason = "";

foreach (var header in message.InternetMessageHeaders)
{
    if (header.Name == "X-Microsoft-Antispam-Mailbox-Delivery")
    {
        if (header.Value.Contains("noattr:1"))
        {
            isSoftBounced = true;
        }
    }
    else if (header.Name == "X-Forefront-Antispam-Report" || header.Name == "X-Microsoft-Exchange-Diagnostics")
    {
        bounceReason = header.Value;
    }
}

if (isSoftBounced)
{
    Console.WriteLine("The mail was soft bounced.");
    Console.WriteLine("The reason for the bounce was: " + bounceReason);
}
else
{
    Console.WriteLine("The mail was not soft bounced.");
}

Test:

Hope this helps.

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