To assist you better with this, have you provisioned your WebApp on Azure App Service WebApp? How is SharePoint integrated?
If you haven’t done this already, kindly navigate to the Azure AI studio select the concerned Subscription and the Region to check the quota limit and the usage. To help validate if you have exhausted the quota limits. Understanding rate limits
Additionally, if you haven’t done, please try the following:
- Capture and review browser network trace to fetch more info about the error.
- For App Service WebApp, you may leverage App Service diagnostics from Azure Portal> Navigate to your App Service app in the Azure Portal.
--In the left navigation, click on Diagnose and solve problems
- Review and run- “Configuration and Management and “Availability and Performance” options.
Kindly let us know, I’ll follow-up with you further.