Hi Hao Shi,
You need to change the name of the function app name to another unique, because the name that you are currently using is taked by another funtion app.
Function App name must be globally unique amongst all Azure Functions Name that identifies your new function app. Valid characters are a-z (case insensitive), 0-9, and -. https://learn.microsoft.com/en-us/azure/azure-functions/functions-create-function-app-portal#create-a-function-app
Let me know if this help you.
Luis
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