Hi,
Can you check the deployment process over here as there are initial configuration and setup for App Service on Linux assuming it is a Java App? If not check other supported Apps in the same link - https://learn.microsoft.com/en-us/azure/app-service/quickstart-java?tabs=javase&pivots=platform-linux-development-environment-azure-portal&view=azure-java-stable
Also verify the troubleshooting steps here - https://learn.microsoft.com/en-us/troubleshoot/azure/app-service/faqs-app-service-linux?toc=%2Fazure%2Fapp-service%2Ftoc.json&view=azure-java-stable
Hope this helps.
JS
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