Forum Discussion
503 UnknownError for all /sites calls
I've run into scenarios where 503 was indeed caused by throttling, but that should go away in time. The easiest way to confirm whether it's throttling related is to run a test with a new AppID, preferably from a different tenant.
FWIW, the endpoint does work as expected here, but that's no guarantee that a service-side issue is happening somewhere in the vast MS cloud. Support is provided for the Graph API as well, so tell the agent you worked with to stop slacking and transfer you to the corresponding team. These forums are not an official support channel and there's barely any presence from Microsoft folks on them, outside of the blog section.
The issue is still persisting and Microsoft Support has been no help. Their regular support channels bring me to people that say they are trained with the 365 apps and cannot help with actual Graph API calls. Attempting to make a request through the Azure Admin center prompts me to purchase a service subscription before being able to get any help.
As said the call gives 503 error. I then went ahead and removed all the site permissions from my app registration and waited a day before trying again. Regardless of the permissions the app is given, so long as the token is valid I get a 503 error, so it is returning that before even validating app permissions. The only time I do not get a 503 error is when I purposefully provide an incorrect access token for example using graph_header = {"Authorization" : f"Bearer {graphAuth()[:-1]}"} In that case I get a 401 error which is expected since the token is invalid, but so long as it is a real token the request never checks permissions before giving me an UnknownError. I also did try creating a new app registration in Entra and making the request with that though the 503 error remained.
Between the time the error has been happening, the inability to get direct Microsoft support, and the lack of information coming from the error, I am at a loss of how to proceed.