unable to get my emails via graph API - rest

Question

I'm using the graph api to fetch my emails. and I'm using a postman client, I'm getting the authorize token and sending it to the api as header.
When I run the below query.
https://graph.microsoft.com/v1.0/me
the response that I get is
{
"#odata.context": "https://graph.microsoft.com/v1.0/$metadata#users/$entity",
"id": "someId",
"businessPhones": [],
"displayName": "MyName",
"givenName": "MyFirstName",
"jobTitle": "MyDesignation",
"mail": "myEmailAddress",
"mobilePhone": "MyMobileNumber",
"officeLocation": "MyWorkLocation",
"preferredLanguage": null,
"surname": "MySurName",
"userPrincipalName": "MyEmailAddress"
}
and when I try to run the below query.
https://graph.microsoft.com/v1.0/me/messages
The response that I get is as below.
{
"error": {
"code": "ResourceNotFound",
"message": "Resource could not be discovered.",
"innerError": {
"request-id": "59a0a25b-67c4-4fe8-8aff-eb035b974a4b",
"date": "2017-03-10T14:09:13"
}
}
}
Also tried the below URL to get the emails.
https://graph.microsoft.com/v1.0/me/mailFolders/Inbox/messages
I get the same response as above.
Finally I tried
https://graph.microsoft.com/v1.0/me/mail
Here the response that I got is
{
"#odata.context": "https://graph.microsoft.com/v1.0/$metadata#users('someRandomId')/mail",
"value": "myEmailAddress"
}
please let me know how can I get my emails shown.
In the portal(https://apps.dev.microsoft.com), I've the below things enabled for this application.
Thanks