503 error on 2019-10 REST api for inventory update

[sgm407]

Getting this error:

Run:Shopify: Synch Inventory was run on 9/8/2021 11:15:00 AM
Duration:00:00:04.8436563
Status:Failed (Enabled)
Message(s):Synch Inventory: The remote server returned an error: (503) Server Unavailable.

Seems to be inconsistent service on Shopify side.

Shopify Support strangely suggested that Shopify would consider fixing this if we posted a message here...

[GrahamS]

Hello @sgm407 ,

503s are an uncommon issue, however we do see them from time to time. In my experience, the most common reason behind an app encountering 503s is due to a throttle being applied. 

API calls are subject to rate-limiting, which means that only a certain amount of requests can be processed per minute. If an app attempts to exceed the rate maximum, or starts to exhibit bot-like behaviour, the IP/app can have a temporary throttle applied and the requests will be blocked from the server, resulting in a 503.

I would strongly recommend approaching your app developer and have them review their call rate. If the issue is intermittent rather than constant, and the error is 503, then it's a strong likelihood that their issue is automated temporary throttles on their app. They should be able to resolve this by reducing the call rate where necessary.

Best,

Graham