Requesting Microsoft Graph /users/me/sendMail returns 404 - microsoft-graph-api

Question

We implemented oauth2 microsoft graph integration using node sdk. Mostly we use it for reading and sending emails. We already have some customers using our integration, but there's one customer that we are not able to get / send emails from his account. we get a 404 for everything we try to do using his access/refresh token.
this is one example:
POST https://graph.microsoft.com/v1.0/users/me/sendMail
Content-type: application/json
Content-length: 512
{
"message": {
"subject": "...",
"body": {
"contentType": "Text",
"content": "..."
},
"toRecipients": [
{
"emailAddress": {
"address": "...#....com"
}
}
],
}
}
And the response we are getting is:
{
"statusCode": 404,
"code": "ResourceNotFound",
"message": "Resource could not be discovered.",
"requestId": "b5f8efca-53ff-4cf1-978e-c4f745fcbbc1",
"date": "2018 - 01 - 20 T23: 13: 27.000 Z",
"body": {
"code": "ResourceNotFound",
"message": "Resource could not be discovered.",
"innerError": {
"request-id": "b5f8efca-53ff-4cf1-978e-c4f745fcbbc1",
"date": "2018-01-20T23:13:27"
}
}
}
Looking for some similar issues, we found Office365 API returns 404 on GetCalendars on some accounts
where they say that the customer's mailbox might not be hosted in Office 365.There's a way to check using the requestId if this is the problem with our request? Or there's a way to find out without needing to ask the customer to try to sign in using OWA?

Answer 1

The URL https://graph.microsoft.com/v1.0/users/me/sendMail isn't correct. It should be https://graph.microsoft.com/v1.0/me/sendMail.