503 error when trying to get todo lists

Question

There was already a question some months ago but no resolution was found. So I am asking again.

My /me/todo/lists call is failing with a very unuseful 503 server error.
It does not seem to be a permission error because I got a 403 error when I forgot to use the scope Tasks.ReadWrite at first.
It also does not seem to be a throttling issue because I dont't get a "retry-after" header in the response. Also I would expect a 429 error in case of throttling.

Additional information:
It works on Graph Explorer with the same account.
The endpoint /me (To receive account information) works (In my code).

The error response:
{
"error": {
"code": "UnknownError",
"message": "The service is unavailable.",
"innerError": {
"date": "2021-03-31T14:53:42",
"request-id": "b47b308e-c0b3-444d-8392-2c5979e9c48f",
"client-request-id": "b47b308e-c0b3-444d-8392-2c5979e9c48f"
}
}
}

Answer 1

Same error for me. /me works fine but got 503 error from /me/todo/lists.

I retrieved access token with below permissions involves Tasks.ReadWrite

{"token_type":"Bearer","scope":"Tasks.ReadWrite User.Read profile openid email","expires_in":3599,"ext_expires_in":3599,"access_token": ....

However I got 503 error for curl command request.

{
"error": {
"code": "UnknownError",
"message": "The service is unavailable.",
"innerError": {
"date": "2021-04-01T13:24:41",
"request-id": "ef405fae-8cdb-46cf-941e-c42cac871b45",
"client-request-id": "ef405fae-8cdb-46cf-941e-c42cac871b45"
}
}
}

I got 503 error in Graph Explorer as well.