Remote Server Error (429)
Resolve Microsoft throttling during SharePoint migration.
Error Message
SharePoint Migration Error
Error: [Target Connector] – The remote server returned an error: (429)
HTTP 429 indicates rate limiting has been applied by Microsoft.
What Happens
Cause
The error occurs when you initiate too many users simultaneously. The target system (Microsoft SharePoint/OneDrive) terminates connections due to its throttling policy.
Microsoft Throttling Policy
Microsoft enforces rate limits to protect its services from being overwhelmed. When too many API requests are made in a short time, the service responds with HTTP 429 (Too Many Requests) and forcibly closes connections.
Solution
Batch Your Migrations
1 Wait and Retry
Restart migrations at a later time when the throttling has lifted.
2 Use Smaller Batches
Start user migrations in batches of 15-20 users at a time to avoid triggering Microsoft's throttling mechanisms.
3 Stagger Start Times
Instead of starting all batches simultaneously, stagger them with short delays between batches.