Hi @Siva Prasad , I understand that you are using App Service for 2-tier app but it times out when your SQL DB takes 5 minutes to respond.
App Service uses Load Balancer (internally, you can't access the Load Balancer configuration) and it times out after 230 seconds on Windows app, 240 seconds on Linux app. I'd suggest you to look at possibility of using loosely coupled architecture rather than real-time, such as using a Service Bus.
More info: loosely coupled communications.
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