2023-12-05 Microsoft Graph Calendar Sync Limitations

100Yes, we support the Graph API, we do not recommend it as a best practice yet. Some of our initial customers have experienced challenges that we or Microsoft cannot help them with, so we need to prevent these issues from occurring. Please see below:

As Riva has been actively developing and deploying the new Microsoft Graph API connector for Sync, we have noticed that some customers may experience calendar syncing issues, and the following error:

"Poll Error - [ServerError] GraphCalendarDataProvider.a: Error trying to retrieve Calendar events. StatusCode:ServiceUnavailable Code: generalException Message: Unexpected exception returned from the service."

We have made some improvements  and optimizations with our code as it relates to the Graph API, and have opened support cases with Microsoft.

Below is the response from the Microsoft Engineering team:

"Microsoft Engineering investigated the logs and confirmed that API call is failing due to timeout from Graph waiting for REST call to return data.
 
This is due to the number of items being searched, size of the mailbox, number of recurrent items that need to be expanded, causing delay in REST being able to return data in a timely manner.
 
Our Engineering is suggesting reducing the size of data being requested, reduce the number of calendar items being processed so the data does not timeout. In this instance, we regret you to inform this is a by design behaviour.

While we strive to provide a comprehensive and satisfying user experience, we occasionally encounter limitations due to various factors, including technical constraints, resource allocation, and prioritization of development efforts.

Please be assured that we have carefully reviewed your suggestion, and although we are unable to implement it at this time, we have taken note of its significance and potential value for our users. Your feedback will be shared with our product development team for consideration in future updates and enhancements.

Microsoft Engineering would like to inform you that we don’t have a publicly published issue or bug ticket around this issue to track.

We apologize for the inconvenience caused."

With some of our current customers using the Graph connector, we have found that a user count of 100+, and 30000+ calendar sync items per day (item create, update and delete) some users will experience the error above, and will delay syncing for some time.

We recommend to continue using Exchange EWS instead of Graph for the time being, if your user count and calendar sync numbers meet or exceed the aforementioned numbers.

Please contact us for assistance or if you have any further inquiries.