Hey @ian.altgilbers,
I figured it out. You have to add the custom attribute first here which sets the name
value: https://zoom.us/account/user#/advanced
Then you can update the attribute:
{
"custom_attributes":[{
"key":"cbf_8y1njyfmtsk1hnbazp2ucw","name":"test","value":"set from API"
}]
}
Thanks,
Tommy