Google Groups Settings API 500 Error -

i want update group settings via web api request. necessary authorization scopes provided , groups settings enabled. send put request:

body = {     "whocanpostmessage": "all_members_can_post",     "whocanviewmembership": "all_members_can_view" } response = requests.put(     "https://www.googleapis.com/groups/v1/groups/%s" % group_id,     data=json.dumps(body),     headers={         'content-type': 'application/json; charset=utf-8',         'authorization': 'bearer %s' % access_token     } ) 

but server responds:

<response [500]> internal server error  headers: cache-control:  private, max-age=0 content-encoding:  gzip content-length:  122 content-type:  application/json; charset=utf-8 date:  fri, 05 feb 2016 18:36:53 gmt expires:  fri, 05 feb 2016 18:36:53 gmt server:  gse vary:  origin, x-origin  content: {  "error": {   "errors": [    {     "domain": "global",     "reason": "backenderror",     "message": "backend error"    }   ],   "code": 500,   "message": "backend error"  } } 

the same error occurs when use try it! in groups settings api reference.

do have google groups business enabled in domain?