"Overlaps are not supported within TimeSlots" error in Outlook Calendar REST API - office365api

Question

From yesterday I started receiving an error in my service (production environment) when trying to call Outlook Calendar REST API endpoint:
POST https://outlook.office.com/api/v2.0/me/findMeetingTimes
with following request body:
{
"Attendees": [
{
"Type": "optional",
"EmailAddress": {
"Address": "...",
"Name": null
}
},
{
"Type": "required",
"EmailAddress": {
"Address": "...",
"Name": null
}
}
],
"LocationConstraint": {
"IsRequired": true,
"SuggestLocation": false,
"Locations": [
{
"DisplayName": "..."
}
]
},
"TimeConstraint": {
"Timeslots": [
{
"Start": {
"DateTime": "2017-05-05T00:00:00",
"TimeZone": "UTC"
},
"End": {
"DateTime": "2017-05-05T21:59:59",
"TimeZone": "UTC"
}
}
]
},
"MaxCandidates": 1000,
"MeetingDuration": "PT30M",
"IsOrganizerOptional": true }
Here is the response I get:
{
"error": {
"code": "ErrorInternalServerError",
"message": "Invalid value for arg:Overlaps are not supported within TimeSlots, value:
{\"start\":2017-05-04T22:00:00Z,
\"min\":1440}
\r\nParameter name: Overlaps are not supported within TimeSlots"
}
}
Everything was working fine with until yesterday. There were no changes in my service codebase. It seems to be related with some changes in O365 API itself but there are no recent updates in documentation...
Any idea what might be wrong?
UPDATE: Without any modification in the request the server response is now:
{
"error": {
"code": "ErrorInternalServerError",
"message": "Index was outside the bounds of the array."
}
}