The API rate limit for your organisation/application
The API rate limit for your organisation/application pairing has been exceeded
This error occurs if you are trying to send multiple settlements to Xero at the same time.
Xero has a limit on how much data it will accept via its API per minute and so this error means Xero is throttling the amount of data we can send it.
To resolve this error try sending the effected settlements one at a time instead.
You may want to double check that some or parts of the settlements (if split month) have not already been sent over by checking your draft invoices and bills folder, then delete them and try sending the settlements again one by one.