Your API documentation will list preconditions. Common ones:
To break down the terminology:
Use Postman to manually replicate the failing request. Remove headers one by one until it works – the last header removed is your culprit. fast eresource precondition violation reddit
Reddit power users warn: retries are a bandage. Here is the diagnosis. Your API documentation will list preconditions
Some academic databases impose . If you’ve downloaded many PDFs quickly, the proxy may flag you. Reddit power users warn: retries are a bandage
| User | Environment | Trigger | Fastest Fix from Comments | | :--- | :--- | :--- | :--- | | | SAP S/4HANA | Mass updating material masters via BAPI | Add a retry loop with exponential backoff. | | u/api_grief | Custom FastAPI + Postgres | Concurrent PATCH requests to same resource | Implement optimistic locking with If-Match headers. | | u/library_tech | EBSCO Discovery Service (Eresource) | Renewing 500 eBook licenses via batch script | Batch in chunks of 50 with 100ms delays. |