OAuth2 playground 503 Backend Error while Clear event - google-api

Question

I tried to clear the primary calendar events from C#:
calendarService.Calendars.Clear("primary").Execute();
following error was found in google api response:
Google.Apis.Requests.RequestError
Backend Error [503]
Errors [
Message[Backend Error] Location[ - ] Reason[backendError] Domain[global]
]
I also tried to check on the Google OAuth2.0 Playground but it gives me following 503 error:
POST /calendar/v3/calendars/primary/clear HTTP/1.1
Host: www.googleapis.com
Content-length: 0
Content-type: application/json
Authorization: Bearer xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
HTTP/1.1 503 Service Unavailable
Content-length: 177
X-xss-protection: 1; mode=block
X-content-type-options: nosniff
Transfer-encoding: chunked
Expires: Mon, 28 Aug 2017 05:52:33 GMT
Vary: Origin, X-Origin
Server: GSE
-content-encoding: gzip
Cache-control: private, max-age=0
Date: Mon, 28 Aug 2017 05:52:33 GMT
X-frame-options: SAMEORIGIN
Alt-svc: quic=":443"; ma=2592000; v="39,38,37,35"
Content-type: application/json; charset=UTF-8
{
"error": {
"code": 503,
"message": "Backend Error",
"errors": [
{
"domain": "global",
"message": "Backend Error",
"reason": "backendError"
}
]
}
}
After some googling I tried to retry through Exponential-Backoff algorithm also.
but none of these works.

Answer 1

Based from this thread, the Google upload servers started timing out on uploads. There may be nothing wrong with your code other than the fact that you are probably just reporting the error rather than handling the error.
When you get an error like this while using the .Upload method, it indicates that the server is too busy to handle your request within the timeout period. Your program should recognize this error and call the .Resume method to resume the upload.