Syncing Calendar in classic outlook on Windows 11 only works one way with Exchange ActiveSync

D S 0

When using Exchange ActiveSync, calendar syncing in classic outlook on Windows 11 only works in one direction - from server to outlook. However, syncing from Outlook to server on Windows 11 doesn't work as expected. This issue is not present when using Windows 10. I have tested this on two Windows 11 systems and two Windows 10 systems, all with the same Outlook version (2409 Build 16.0.18025.20030). On Windows 10 systems, the syncing works in both directions, but not on Windows 11 systems. (Mail synchronisation works on all systems.)

2 answers

ChristyZhang-MSFT 24,071 Reputation points Microsoft Vendor

2024-10-03T01:56:45.2166667+00:00

Hi @D S ,

Welcome to our forum!

Do you mean that the calendar of your account on your web mail is not syncing in classic Outlook in Windows 11?

If so, what's your account? And how did you add it in classic Outlook in Windows 11?

On the other hand, is there any differences between classic Outlook in Windows 11 and Windows 10?

As i know, when you add your account as POP/IMAP in classic Outlook, the calendar will not sync. Please try to create a new profile (Control Panel>Mail>Show Profiles>add) and add the account as Exchange to check if there're any differences.

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D S 0 Reputation points

2024-10-03T17:33:22.68+00:00

Hi @ChristyZhang-MSFT ,

thanks for you answer.

"Do you mean that the calendar of your account on your web mail is not syncing in classic Outlook in Windows 11?"

-> It has nothing to do with web mail. A calendar entry created with classic Outlook on Windows 11 is not shown on the internal company server. A calendar entry created with classic Outlook on Windows 10 is shown on the internal company server. A calendar entry created on the internal company server is shown in both (windows 10 and windows 11).

"If so, what's your account? And how did you add it in classic Outlook in Windows 11?"

-> It is an internal company account (which supports Exchange ActiveSync). It is add as a Exchange ActiveSync account.

"On the other hand, is there any differences between classic Outlook in Windows 11 and Windows 10?"

-> No.

"As i know, when you add your account as POP/IMAP in classic Outlook, the calendar will not sync."

-> I know.

"Please try to create a new profile (Control Panel>Mail>Show Profiles>add) and add the account as Exchange to check if there're any differences."

-> I tried a new profile and add the account again as Exchange ActiveSync. It does not helped.

I also tried outlook app for android which works as expected in calendar sync.

So Outlook on android an outlook on windows 10 works as expected. Outlook on windows 11 not.

I think it is a problem with windows 11 or the combination of outlook an windows 11 because i tested it with two Exchange ActiveSync account and the issue is on both. With windows 10 and android systems there is no issue.

Is there any (standard) setting in windows 11 which influences Exchange ActiveSync in outlook?

Kind regards

ChristyZhang-MSFT 24,071 Reputation points Microsoft Vendor

2024-10-04T06:47:50.35+00:00

Hi @D S ,

Thanks for your reply!

Outlook on Windows 11 is not shown on the internal company server. A calendar entry created with classic Outlook on Windows 10 is shown on the internal company server. A calendar entry created on the internal company server is shown in both (windows 10 and windows 11).

What's your company server? Exchange on-premise server or Microsoft 365?

As i know, Outlook doesn't support connections to a server that's running Exchange Server by using the Exchange Active Sync protocol. To resolve this problem, we can connect to Exchange by using the standard Exchange connection settings. More information: Outlook doesn't support connections to Exchange by using ActiveSync and error: Log onto Exchange ActiveSync mail server (EAS).

D S 0 Reputation points

2024-10-07T19:51:40.4533333+00:00

Hi @ChristyZhang-MSFT ,

thanks for you answer.

I know the things you wrote.
I think this is not the Problem, because it works under Windows 10.

As I wrote it works fine under Windows 10 and under Android.
So this can not be a problem of the Server.

We have about 20 Windows 10 System wich works all well with Outlook and the Exchange ActiveSync connection.
At this time we only have 2 Windows 11 Systems and both works not as expected with Outlook and the Exchange ActiveSync connection.

Under Windows 11 with Outlook and the Exchange ActiveSync connection the mail synchronisation works fine, but the calendar synchronization only works in one direction.
The direction from Server to Outlook works on Windows 11.
But the direction from Outlook to Server on Windows 11 works not.
The synchronizing error folder is empty on all Windows systems including the Windows 11 Systems.

Kind regards

D S 0 Reputation points

2024-10-07T19:53:11.4+00:00

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2024-10-07T19:55:10.71+00:00

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2024-10-07T20:06:48.3466667+00:00

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D S 0 Reputation points

2024-10-07T20:08:29.8666667+00:00

Hi @ChristyZhang-MSFT ,

thanks for your Answer. I do not understand why my answer will be deleted ... I can not see any violation of your Code of Conduct.

Kind regards

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2024-10-07T20:15:18.51+00:00

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2024-10-07T20:27:28.8233333+00:00

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2024-10-08T19:11:30.59+00:00

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D S 0 Reputation points

2024-10-08T19:12:23.9133333+00:00

Yesterday all my answers and comments were shown as deleted excepted the last one and the one about the code of conduct. So i do not know why they are all back again. I can not delete the unwanted. So I edited it to "deleted" now. Sorry for that.

ChristyZhang-MSFT 24,071 Reputation points Microsoft Vendor

2024-10-09T02:37:19.3533333+00:00

Hi @D S ,

Thanks for your reply!

As i mentioned above, Outlook doesn't support connections to a server that's running Exchange Server by using the Exchange Active Sync protocol. So, the relevant content about Active Sync in Win10 will no longer be supported in the future. The most appropriate way to do this is to connect to Exchange by using the standard Exchange connection settings.

Thanks for your kindly understanding!

D S 0 Reputation points

2024-10-09T17:59:47.4966667+00:00

Hi @ChristyZhang-MSFT ,

Thanks for your Answer.

I understand your Answer but i think that this is not my problem.

As i understand, Outlook generelly supports Exchange ActiveSync but not against a microsoft exchange server. I am right?

The company server is not an exchange server, it is a server wich supports Exchange ActiveSync. The Server do not support standard Exchange connection.

In the link you posten stand under Symptom "When you configure Microsoft Outlook to connect to Microsoft Exchange by using the Exchange ActiveSync (EAS) protocol, you receive the following error message: Log onto Exchange ActiveSync mail server (EAS): The server cannot be found."

I did not get this Error message. The server will be found and i can configure the connection and connect without any Error message. So i do not anderstand the different between the same Version of Outlook on Windows 10 and Outlook on Windows 11. For me it shows like a bug in the combination from Outlook with Windows 11.

Kind regards.
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Gaston 0 Reputation points

2024-10-11T08:44:46.4+00:00

I have the same issue, but it is on Windows 10.
When I add an appointment in my web based calendar, it shows up in Outlook (classic), but the other way around it doesn't work.

Outlook version 2409, build 18025.20140
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Gaston 0 Reputation points

2024-10-11T10:29:46.2933333+00:00

Also works in both way from android apps. Just not in Windows/Office Outlook (classic) with activesync.
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Syncing Calendar in classic outlook on Windows 11 only works one way with Exchange ActiveSync

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