The listener for function 'Function1' was unable to start when running a timer function

Question

I am getting this below error when I am running my timer function app in Azure Cloud. It is just a basic code and I wanted the log to be shown in Insight.

public static class Function1
{
    [FunctionName("Function1")]
    public static void Run([TimerTrigger("0 * * * * *")]TimerInfo myTimer, ILogger log)
    {
        log.LogInformation($"C# Timer trigger function executed at: {DateTime.Now}");
    }
}

Answer 1

Here is the workaround I did to identify this issue cause:

1. Created the Azure Function (Stack: .NET 3.1) of type Timer Trigger with your given timer "0 * * * * *" and the connection string given from the storage account created in Azure portal, which is running successfully (in local):

2. Deleted the Storage account from the Azure Portal and tried to run the function locally which gave me the error: The listener for function Function1 was unable to start.

Recovered the Storage Account and then deployed to the Azure Portal Function App and running successfully in cloud also:

In the Azure Cloud, Yes, as @Skin Said that it would be a Storage Account configuration issue.

Few of the steps to resolve this issue were:

• Check the AzureWebJobsStorage value contains correct the correct storage account connection string.
• Check the Storage account is not deleted.
• Check the Networking Option in the Function App that might be the firewall is blocking/restricting the access to the associated storage account.

Answer 2

It was a firewall issue. Added the appropriate Virtual Network and Su.net under Storage Account > Networking > Firewalls and Virtual Network