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How to Fix Microsoft Graph API Upload Session HTTP 400 Errors
Question details
Users need to resolve an issue where uploading large attachments via the Microsoft Graph API results in an HTTP 400 error.
- Product
- Microsoft Graph API
- Device & OS
- not provided
- Scenario
- Uploading large attachments using the Java Graph SDK or Microsoft Graph API, particularly after the EX637339 service update.
- Observed behavior
- The upload session fails and returns an HTTP 400 Bad Request error instead of successfully processing and uploading the large attachment.
Gather your request details, including timestamps, request identifiers (such as request-id and client-request-id), and your Java Graph SDK version to expedite the support ticket process.
Submit a Microsoft Graph Service Incident via Azure Portal
Since this HTTP 400 error is tied to service updates affecting multiple tenants, escalating it through an official support ticket is the most effective resolution.
This specific upload session issue has been identified as a backend service change related to the EX637339 update. Because it affects multiple customers at the infrastructure level, individual code changes or SDK downgrades will not resolve the problem permanently.
Navigate to the Microsoft Azure Portal and sign in using your administrator credentials.
From the left-hand navigation menu or the top search bar, search for and select 'Help + support', then click on 'Create a support request'.
Under the 'Issue type' drop-down menu, select 'Technical', and then choose the appropriate Azure subscription linked to your environment.
For the service category, choose 'Azure Active Directory App Integration and Development', and then select 'Graph API'.
Provide a summary of the HTTP 400 upload session error. In the details section, paste your request headers, timestamps, client-request-id, SDK version, and the exact error response before submitting.
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Frequently Asked Questions
Why am I getting an HTTP 400 error only on large attachments in Microsoft Graph API?
HTTP 400 errors for large attachments typically occur when the upload session payload exceeds specific chunk size limits, or due to backend service changes like the EX637339 update that introduced stricter validation rules on Microsoft's servers.
What is the correct maximum chunk size for Microsoft Graph API upload sessions?
When uploading large files using an upload session, the chunk size must be a multiple of 320 KiB (327,680 bytes). It is highly recommended to keep individual chunks between 5 MB and 10 MB to ensure upload stability.
Can updating the Java Graph SDK resolve this HTTP 400 error?
If the issue stems from a known Microsoft backend bug affecting upload endpoints, simply updating the SDK may not fix it. However, it is always best practice to ensure you are using the latest version of the Java Graph SDK before submitting a support ticket.
