Troubleshooting: ErrorTooManyObjectsOpened (Rate Limiting)

If you receive a 429 Too Many Requests error or the specific provider error ErrorTooManyObjectsOpened when making requests to a Microsoft grant (Exchange/Microsoft 365), your account has hit its concurrency limit.

Cause:

Microsoft Exchange/Graph APIs strictly limit the number of concurrent connections allowed for any single user account (typically 4 concurrent connections at any given time).

The error indicates that the user's account is actively being used by other applications (e.g., desktop clients, Outlook Web, mobile sync, or other integration services) that are consuming all available connection slots. When Nylas attempts to make an API call, it is rejected because no slots are left.

Resolution Steps (Action Required by Administrator):

1. In Entra admin center, check the sign-in logs:  Check how many applications are calling Graph API.

2. Check Activity logs:  See how many Graph APIs are being made. If the traffic pattern does not align with Nylas usage, it means some other applications are using it.

3. Ask admin to relax the concurrent requesting throttle with self-help-diagnostics.

4. In the Entra portal, force sign off on all other applications.

5. Create an Azure support ticket asking them to identify the root cause of the rate limit. Pass the request ID in the ticket.

Updated October 29, 2025 23:01