Outlook API v2.0 getEvents concurrency litmit

I am using outlook api v2.0 rest api to perform crud operations against calendars and events and have started hitting a rate limit issue.

This one for example is hitting the calendarview endpoint:

GET https://outlook.office.com/api/v2.0/me/calendars/{CALENDAR_ID}/calendarview

RESPONSE HEADERS

• Rate-Limit-Limit=10000
• Rate-Limit-Remaining=9982
• Rate-Limit-Reset=2019-10-23T15:27:11.409Z
• Retry-After=1
• RateLimit-Exceeded=MailboxConcurrency
• RateLimit-Scope=Mailbox
• Transfer-Encoding=chunked
• X-Proxy-BackendServerStatus=429
• X-Powered-By=ASP.NET
• X-RUM-Validated=1

RESPONSE BODY

{
    "error": {
        "code": "ApplicationThrottled",
        "message": "Application is over its MailboxConcurrency limit."
    }
}

At first I thought it was the 10.000 requests per 10 minutes period but it seems I am hitting a different one.