options for custom field using API

[Yellalingh Margonda]

Hi I am trying to get the option available for the custom filed using this api

l = "https://your-domain.atlassian.com/rest/api/3/customField/customfield_10135/option

it returns the 404 error. I am following this document https://developer.atlassian.com/cloud/jira/platform/rest/v3/api-group-issue-custom-field-options/#api-rest-api-3-customfield-fieldid-option-put 

I have the admin access. Can someone please help me in writing a api to retrieve the custom field options 

[Nic Brough -Adaptavist-]

Dashboards don't have custom fields.