REST API adding name with spaces to custom field doesn't work

[DeniseThompson397]

Hi, There are a couple of similar questions on this but I am unable to get an answer.  I am trying to create a JIRA using VBA and Json and one of our custom fields contains a blank in the name and I have tried most things including single quotes and using %20 but my job fails with

"{"errorMessages":[],"errors":{"customfield_10021":"Option value 'firstword nextword' is not valid"}}"

When I replace the customfield with a 1 word value without spaces it works.  Any ideas?

'{

'   "fields": {

'     "project": {

'         "key": "TESTproject"

'     },

'     "summary": "test summary",

'     "description": "this is a test",

'     "issuetype": {

'         "name": "Issue"

'     },

'     "components": [

'         {

'           "name": "None"

'         }

'     ],

'     "customfield_10021": [

'         {

'           "value": "firstword nextword"

'         }

'     ],

'     "customfield_12030": {

'        "value": "another value"

'     }

'   }

'}