I am somewhat confused by the API Guide on this
The Field ID I use is what I get as ID from the custom field which is a UUID that is 8-4-4-4-12 bytes something like "ab95d298-4db2-42db-a035-cb9589b29d9e" I've also tried just using the first segment of 8 bytes "ab95d298"
and I send the following to set a label type custom field
{
"value": "b9579504-2539-41e5-8324-36b6f2fc173d"
}
I get 400 Bad Request
While I'm at it, are there any plans to add this functionality to the Zapier Integration