Office365 rest api returns 404 on a get calendars operation -

i've been using office365 rest api calendars while now, , experienced wierd 1 of new customer. when calling "/api/v1.0/me/calendars" endpoint, 404 blank body. not seem authorization issue can exchange access token without issue.

here response headers.

{ "content-length"=>["0"], "server"=>["microsoft-iis/8.0"], "request-id"=>["183391ab-9f6b-4828-b8bc-3fd47f7c5d9f"], "set-cookie"=>["clientid=vmhpfwyg0gtcmmsgarf0a; expires=sat, 16-jul-2016 11:50:14 gmt; path=/; secure; httponly"], "x-calculatedbetarget"=>["bn1pr04mb469.namprd04.prod.outlook.com"], "x-backendhttpstatus"=>["404"], "x-diaginfo"=>["bn1pr04mb469"], "x-beserver"=>["bn1pr04mb469"], "x-powered-by"=>["asp.net"], "x-feserver"=>["blupr16ca0002"], "date"=>["fri, 17 jul 2015 11:50:15 gmt"] }