Remove "schedule": null from your parameters.

If you want to specify a schedule (typically used with 'condition': 'violated' or 'condition': 'exceeded'), use a format like this:

schedule: 'Date pattern'

For more information about date pattern or other schedule parameters, see man isi-schedule.

Examples below of a couple of json strings that work.  This is from a python program so you would extract the info between { } to put in your 'curl' tests.

# This if for an 'exceeded' condition, notice there's no 'schedule' param.

    notjson_exceeded = json.dumps({'holdoff': 0, 'action_email_address': 'my.email@isilon.com', 'threshold': 'hard',

                                                     'action_email_owner': False, 'email_template': '/ifs/template/homedir_hard.txt',

                                                     'action_alert': True, 'condition': 'exceeded'})

# This is for a 'violated' condition, notice the 'schedule' param.  I also specified a 'holdoff' value of 1 day (86400 sec).

    notjson_violated = json.dumps({'holdoff': 86400, 'action_email_address': 'my.email@isilon.com', 'threshold': 'hard',

                                                  'action_email_owner': False, 'email_template': '/ifs/template/homedir_hard.txt',

                                                  'action_alert': True, 'condition': 'violated', 'schedule': 'every day at 2am'})

The resulting listing from CLI is:

isi quota quotas notifications list /ifs/data/quota_test directory -v

     Threshold: hard

     Condition: exceeded

      Schedule: -

       Holdoff: Now

   ActionAlert: Yes

    EmailOwner: No

NotifyAddress: my.email@isilon.com

Email Template: /ifs/template/homedir_hard.txt

--------------------------------------------------------------------------------

     Threshold: hard

     Condition: violated

      Schedule: every day at 2am

       Holdoff: 1D

   ActionAlert: Yes

    EmailOwner: No

NotifyAddress: my.email@isilon.com

Email Template: /ifs/template/homedir_hard.txt