It's all been working fine untill the past couple of days, when suddenly every 4th or 5th request to AJAX Api (shipping_rates.json) started returning 429 Too many requests. No Retry-after header, no bucket level (which I don't even know if leaky bucket is being used or not) - just no information about how long we should wait between requests. Seems like now there is a limit of about 3 requests per 30 seconds but not really sure, hard to understand. Does anyone know what might have changed in Shopify or what other problem might have started causing these errors?
We are getting the exact same issue today. We have tested this in about 4 stores and can confirm that something is wrong there and 429 Too many requests is coming frequently.
@Shopify support please help us in this regard