Cant get the right format to update a tasks custom field(s) via API using Form (not json)

I;m really hoping that someone can help me with this.

I’m using Form as this is easier to build up from variables as part of a Microsoft flow project.

Custom field is text

            "id": 1234,
            "gid": "0987",
            "enabled": true,
            "name": "mytext",
            "text_value": "value1",
            "type": "text"

I want to update the value of a custom field for a task but i just cant get the context right for the Key pair (I am using Postman for testing)

I found this on the asna sight

" SETTING CUSTOM FIELD VALUES Custom fields are set with PUT requests similarly to setting other fields on tasks; the format of the request is to set the id to the new value. That is, custom_fields:{custom_field_id:custom_field_value}

Custom fields of type text are set by passing in custom_field_id:string Custom fields of type number are set by passing in custom_field_id:number Custom fields of type enum are set by passing in custom_field_id:enum_value_id"

But this doesn’t appear to work in my form requests.

Can anyone tell me where I am going wrong please?

Thank you in advance.

Can you post a Postman screenshot of what you’re currently trying? I think that would help us to guide you.