Hello Vidhya Bhushan Bahl,
Welcome to the Microsoft Q&A and thank you for posting your questions here.
I understand that your Azure Open AI chat deployment failed from Azure AI Foundry.
Yes, reading through the error messages, it is one of the common errors. Because, the error message you're seeing, 503 Server Unavailable, indicates that the server is temporarily unable to handle the request. This can be due to various reasons, such as high memory/CPU usage, application crashes, or service interruptions. Follow the best practices to resolve the issue in typical scenario: https://learn.microsoft.com/en-us/azure/app-service/troubleshoot-http-502-http-503 and https://learn.microsoft.com/en-us/azure/ai-studio/how-to/troubleshoot-deploy-and-monitor?source=recommendations
I hope this is helpful! Do not hesitate to let me know if you have any other questions.
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