Azure Functions Runtime is unreachable. Click here for details on storage configuration.

Azure Functions Runtime is unreachable. Click here for details on storage configuration.

Issue:

·       Azure Functions Runtime is unreachable.

·       Not able to do anything with this function.

·       Functions are not visible

Solution:

A very common issue which we face in Azure functions is,

Azure Functions Runtime is unreachable. Click here for details on storage configuration.

This exception is mostly related to Storage account. Either your storage account is not accessible, or credential are invalid, or storage account deleted.

When You see these types of issue, Your first troubleshooting step should be collecting the network trace immediately.

Please follow below steps to collect the network traces,

•       Hit F12 on your browser

•       Refresh browser (F5) - This will clear session caches

•       Reproduce the issue.

•       Export network trace as HAR file (Save all as HAR on Chrome/Edge/IE)

Once you have network trace then you can open it through Fiddler which will definitely give some information about some of the API failure.

While investigating this API failure I observed lot of messages related to Network.

You can click on any of the API failure (red color)  and click on preview (right side.)

As the message says something about Network, I quickly verified the network setting but I was getting this issue in other networks also that means this issue is not pertaining to the network.

  

I then checked Storage Account for this function. You can get the information about storage account from your application setting and refer either AzureWebJobsStorage or WEBSITE_CONTENTAZUREFILECONNECTIONSTRING

Reference: https://docs.microsoft.com/en-us/azure/azure-functions/functions-create-function-app-portal#storage-account-requirements

I further checked and confirmed unavailability of storage account. 

 Somehow my storage account was deleted by someone which was causing that issue. I created a new function app and was able to add a new function successfully.

So whenever you face this issue please check the network trace and storage account availability.

There might be other reason also. If your storage account is not deleted then you can check,

• Are you able to tcpping your storage account form function app KUDU?
• Do you have any firewall setting at storage account side which is preventing your function to connect with storage account.
• Please check storage account connection string properly in your function app Application Setting section. And if possible get the storage account connection setting again and replace.

I believe this helps. Please share your feedback.