PartnerIntegrationService call failed: Request failed with status code 400 during Developer Onboarding (Account Setup stuck)

If this is a new zero-fee Individual registration, email [Email]; if it is a Company registration, open a Windows Developer Support request at https://aka.ms/windowsdevelopersupport. ^1^ ^2^

What to include

Submit the following in the email or private support request:

• Issue: Account Setup remains blocked at Step 4.
• Endpoint: POST https://storedeveloper.microsoft.com/api/onboarding
• Exact response: PartnerIntegrationService call failed: Request failed with status code 400
• The complete response body, unmodified. Include INTERNAL_ERROR only if it actually appears there.
• The request’s correlation/reference ID, if present in the response headers or body.
• Exact failure time converted to UTC: 2026-11-06 [time] UTC+9, plus the corresponding UTC time.
• Account type: Individual or Company.
• Country/region and onboarding locale (ko-KR).
• Confirmation that identity and address verification completed successfully.
• Screenshot showing Step 4 and the error, with personal information hidden.
• A short summary of the troubleshooting already completed: InPrivate session, cleared browser data, standardized address, and retries over multiple days.

A closely matching Store onboarding incident—verification completed, followed by the same PartnerIntegrationService HTTP 400 during final account creation—was directed to Store developer support for investigation of the onboarding workflow. ^3^

Suggested subject:

Store developer onboarding blocked at Step 4 — PartnerIntegrationService HTTP 400

Suggested request:

Identity and address verification completed successfully, but account creation consistently fails at Step 4. Please inspect the failed PartnerIntegrationService request and the account provisioning state. If the onboarding record is incomplete or inconsistent, please repair or reset it so registration can complete.

The HTTP 400 alone does not establish that the provisioning record is corrupted. Microsoft Support must inspect the account-specific logs and determine whether repair or reset is necessary. Microsoft Q&A participants cannot access those logs or modify the onboarding state.

Optional HAR trace

A HAR file is useful supporting evidence but is not required before initially contacting support. If support requests one:

1. Open Edge or Chrome and load the failing onboarding page.
2. Press Ctrl+Shift+I and select Network.
3. Clear existing requests, then start recording.
4. Reproduce the Step 4 failure once.
5. Stop recording and select Export HAR.
6. Review the file and send it only through the designated private support channel.

HAR files can contain authentication tokens and personal data; do not attach one to this public Q&A thread. Microsoft’s Partner Center diagnostic guidance documents the capture procedure and the sensitivity of HAR files. ^4^

Since retries, browser isolation, cache clearing, and address correction have already failed, repeating those client-side steps is unlikely to add useful evidence. The next action is the account-type-specific escalation above.

References

1. Free developer registration for individual developers
2. Steps to open a developer account
3. Store developer account creation fails – INTERNAL_ERROR (PartnerIntegrationService 400) - Microsoft Q&A
4. Send diagnostics to Microsoft