I have a simple bit of JSON from an Azure Traffic Manager request, so ideally it would be stored in a blob storage account that is marked with a public access policy to read the blob. When I attempt this - using external endpoint in ATM - I get a 400 HTTP response.
The endpoint shows online in the portal, which is interesting since issuing that URL through the browser also results in a 400 error. I have the health probe pointed at a public blob at the $root container.
My second attempt was to then try an Azure function as the endpoint, and in this case the health probe results in a 'stopped' state. From older articles it appeared this would be returned for a basic App service plan (this is a consumption plan), but I presume that's outdated at this point?
What's the resolution here? This shouldn't be this hard!
According to your description, I checked this issue on my side and I could encounter the same issue as you mentioned. Then I found issues about Traffic Manager and Blob Storage and Integration of Azure Functions with Traffic Manager.
Per my understanding, Traffic Manager does not support integration with Blob Storage, you could add your feature request here.
For integrating with Azure Functions, you need to make sure your Web Apps at the Standard SKU or above are eligible for use with Traffic Manager. For web apps below Standard SKU, you could leverage Azure Functions Proxies. Here are some references, you could refer to them: