Power Automate 429 "Too Many Requests" — how to fix
A 429 means Power Automate hit the connector's rate limit — too many calls in too short a window, usually from a loop calling an action on every item or several flows running at once. Immediate fix: if concurrency is turned on for the Apply-to-each, lower it (loops run one item at a time by default), add a Delay between calls, or add an exponential-backoff retry policy on the action. Durable fix: batch the operation or filter rows before the loop so you call the connector less often.
Why it happens
Connectors and services enforce rate limits (requests per minute/connection). A loop that calls an action on every item, or many concurrent runs, quickly exceeds them and the service returns 429.
Excel Online (Business) and SharePoint are the usual suspects
If your flow loops over rows in an Excel table or items in a SharePoint list — one "Update a row" or "Update item" call per record — you'll hit 429s far sooner than with most other connectors, because both enforce noticeably tighter limits than an average API connector. The exact numbers change over time and by license, so check the current values in Microsoft's connector reference rather than assuming a fixed number.
The fix is the same principle as above, applied specifically here: for Excel, avoid one action per row — batch the update with a single Office Scripts run instead of looping, or use "Add a row into a table" in bulk mode where available. For SharePoint, filter server-side with an OData Filter Query so the loop only touches the rows that actually changed, instead of writing to every item on every run.
How to fix it
- 1Check concurrency: Apply to each runs one item at a time by default. If concurrency control has been turned on (Settings on the Apply to each), lower the Degree of Parallelism or set it to 1.
- 2Add a Delay action inside heavy loops to space out calls.
- 3Batch operations where the connector supports it instead of calling the action once per row.
- 4Add a retry policy (exponential) on the action so transient 429s recover automatically.
Prevent it
Filter rows before the loop so you only process what you need, and avoid triggering many flow runs at once on bulk changes.