REST API create issue with custom fields. cannot be set. It is not on the appropriate screen, or unknown.

[Matt H]

I'm getting Field 'customfield_10800' cannot be set. It is not on the appropriate screen, or unknown.

When I log into JIRA with the user Im using REST with the default screen has the custom fields but they are in another tab. Does that matter?

I've read a lot of issues that are similar but I have yet to get a custom field to get added.

...
EMAIL_CLIENT = "customfield_10800"
CLIENT_EMAIL_ADDY = "customfield_10600"
ASSIGNEE_GROUP = "customfield_10501"
CLIENT_NAME = "customfield_10601"
FAC_ID = "customfield_10700"
ISSUE_KEY = "key"
 
_summary = 'testing new ticket from hc'
_desc = _summary
issue_dict = {

    'project':{'key':'SDEV'},
    'summary':_summary,
    'description':_desc,
    'issuetype':{'name':'Task'},
    'customfield_10800': "text@example.com",
    CLIENT_NAME: "last_name, first_name",
    FAC_ID : "168709"
}

print jira.create_issue(fields=issue_dict)

[Rich Scire]

I've seen this error in two instances:

The first is that the field is not actually on any screen for the issue type. In this case, the URL specified the wrong issue type id so was inadvertently creating the wrong issue type. The incorrect issue type did not have the  field identified in the error.

The second instance was that the field in the error was on the screen but it had a null context. That is, the global context specified a set of issue types but the one I was trying to create wasn't one of them. I added the issue type to the context and it then worked fine.