The email with an attached ICS file sent using Azure is not recognized as a calendar event by Outlook

Question

The email with an attached ICS file sent using Azure is not recognized as a calendar event by Outlook

耀烽郑 0

During the process of sending an email using Azure's Java SDK, the observed phenomenon is that the ICS file sent via Azure is only recognized as an attachment, but it can be recognized as a calendar event and displayed correctly by other email clients.

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I currently have two questions. Firstly, how does Outlook determine whether an email should be recognized as a calendar event, similar to the example shown below? Secondly, why is the email sent via Azure not recognized as a calendar event? I have already consulted Azure, and they confirmed that there are no issues with their email sending. Therefore, I would like to inquire about the investigation of the issue on the Outlook side.

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navba-MSFT 27,610 Reputation points Microsoft Employee Moderator

2023-12-18T07:27:45.6566667+00:00

@耀烽郑 Welcome to Microsoft Q&A Forum, Thank you for posting your query here!
I have removed the Azure channel tag from this thread.
I have retained the Outlook channel tag on this thread so that the community experts can assist you further on this.
SokiGuo-MSFT 31,726 Reputation points Microsoft External Staff

2023-12-18T09:06:26.72+00:00

Hi @耀烽郑

Welcome to our forum!

Please kindly understand that the Outlook tag here we mainly focus on general issues about Outlook desktop client, and we know little about Azure.

Firstly, how does Outlook determine whether an email should be recognized as a calendar event, similar to the example shown below?

Outlook determines whether an email should be recognized as a calendar event based on the sender, content, and event type of the email. Such as airlines, hotels, car rentals, parcel delivery, billing, meal reservations, etc. More information, please see: Automatically add events from your email to your calendar - Microsoft Support.

Also, in order to troubleshoot if the issue is related to the Outlook client, please provide more details:

Will these calendar events be reflected in the calendar?

Having the same problem on Outlook web?

Please try to send calendar events via Outlook client if there is the same problem.
耀烽郑 0 Reputation points

2023-12-19T02:39:40.0266667+00:00
Hi @SokiGuo-MSFT

I would like to understand the code-level details on how Outlook determines whether an email should be recognized as a calendar event. For example, are there any required parameters in the email's ICS file? Are there any necessary header information that must be included when using a third-party SDK to send emails to Outlook? The link you provided covers a wide range of topics, which seems too broad for my specific question. Could you please provide a more focused explanation?

Then,I would like to provide some insights and answers to the questions you raised for your reference:

When I send an ICS file using the Azure SDK, it doesn't appear as a calendar event in my Outlook. Instead, it is treated as a regular attachment. However, I can still open the file using Outlook, and it displays the content as a schedule.

The same issue occurs when accessing Outlook through the web interface. You can refer to the attached image for the display effect in Outlook web.

Currently, I am unable to send emails using the Outlook client because I intend to utilize the Azure SDK for sending emails and expect to receive the calendar events correctly in Outlook.

I hope this information helps. If you have any further questions or need additional assistance, please let me know.
Felipe Carvalho 0 Reputation points

2026-01-16T10:35:25.0766667+00:00

Although it is old post, I am having the same issue. After some trials and errors, once I remove the ContentId element from the attachment object it works. I did not know the reason yet, but so far solved.

1 answer

Your answer

navba-MSFT 27,610 Reputation points Microsoft Employee Moderator

2023-12-18T07:27:45.6566667+00:00

@耀烽郑 Welcome to Microsoft Q&A Forum, Thank you for posting your query here!
I have removed the Azure channel tag from this thread.
I have retained the Outlook channel tag on this thread so that the community experts can assist you further on this.
SokiGuo-MSFT 31,726 Reputation points Microsoft External Staff

2023-12-18T09:06:26.72+00:00

Hi @耀烽郑

Welcome to our forum!

Please kindly understand that the Outlook tag here we mainly focus on general issues about Outlook desktop client, and we know little about Azure.

Firstly, how does Outlook determine whether an email should be recognized as a calendar event, similar to the example shown below?

Outlook determines whether an email should be recognized as a calendar event based on the sender, content, and event type of the email. Such as airlines, hotels, car rentals, parcel delivery, billing, meal reservations, etc. More information, please see: Automatically add events from your email to your calendar - Microsoft Support.

Also, in order to troubleshoot if the issue is related to the Outlook client, please provide more details:

Will these calendar events be reflected in the calendar?

Having the same problem on Outlook web?

Please try to send calendar events via Outlook client if there is the same problem.
耀烽郑 0 Reputation points

2023-12-19T02:39:40.0266667+00:00

Hi @SokiGuo-MSFT

I would like to understand the code-level details on how Outlook determines whether an email should be recognized as a calendar event. For example, are there any required parameters in the email's ICS file? Are there any necessary header information that must be included when using a third-party SDK to send emails to Outlook? The link you provided covers a wide range of topics, which seems too broad for my specific question. Could you please provide a more focused explanation?

Then,I would like to provide some insights and answers to the questions you raised for your reference:

When I send an ICS file using the Azure SDK, it doesn't appear as a calendar event in my Outlook. Instead, it is treated as a regular attachment. However, I can still open the file using Outlook, and it displays the content as a schedule.

The same issue occurs when accessing Outlook through the web interface. You can refer to the attached image for the display effect in Outlook web.

Currently, I am unable to send emails using the Outlook client because I intend to utilize the Azure SDK for sending emails and expect to receive the calendar events correctly in Outlook.

I hope this information helps. If you have any further questions or need additional assistance, please let me know.
Felipe Carvalho 0 Reputation points

2026-01-16T10:35:25.0766667+00:00

Although it is old post, I am having the same issue. After some trials and errors, once I remove the ContentId element from the attachment object it works. I did not know the reason yet, but so far solved.

Answer 1

Outlook determines whether an email should be recognized as a calendar event based on the content type of the message and the attachment. The content type of the message should be [multipart/alternative] or [multipart/mixed] , and the content type of the attachment should be [text/calendar]. The attachment should also have a valid file extension and follow the iCalendar format.ics.

Secondly, the reason why the email sent via Azure is not recognized as a calendar event by Outlook may be due to the way Azure’s Java SDK handles the attachment. Azure’s Java SDK may not set the content type of the attachment correctly, or it may encode the attachment in a way that Outlook cannot parse. Therefore, you may need to manually specify the content type and encoding of the attachment when sending the email via Azure’s Java SDK.

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The email with an attached ICS file sent using Azure is not recognized as a calendar event by Outlook

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