After making 20 calls to computer vision cloud service, the service starts to return 404 - not found

Question

Hello Everyone,

I have a rpa project(KofaxRPA) which sends parking receipt images to azure computer vision cloud service, which then reads information from image and returns the results.

For the first 20 images the computer vision service works and returns 200 = successfull,

Starting from 21th image and so on the computer vision service always returns 404 = NotFound

What might be the reason for this?

Answer 1

Hi Burak Cankur,

Thanks for Reaching the Microsoft Q&A Forum

The behavior you're experiencing is likely related to the rate limits of the F0 (free) tier for Azure's Computer Vision service. According to the information you've provided, the F0 tier allows up to 20 calls per minute and 5,000 calls per month.

When you reach the 21st call (or beyond), the service might return a 404 Not Found error because the rate limit per minute has been exceeded.

Here are a few steps to address this:

• Check the Rate Limit: Ensure that you're not exceeding the 20 calls per minute or 5,000 calls per month limit. If your RPA project is sending images more frequently than allowed (even if it's just over 20 per minute), that could cause the issue.
• Switch to S0 (Standard) Tier: If the call frequency is higher than the free tier supports, consider upgrading to the S0 (Standard) tier, which offers unlimited predictions per month and a higher calls per minute rate (20 transactions per second).

If you're still encountering issues after considering these factors, you can review the error details (besides the 404) to get more insights on the root cause.

Please check https://learn.microsoft.com/en-us/azure/ai-services/custom-vision-service/limits-and-quotas?source=recommendations