400 Bad Request - Invalid Enum/Dropdown Value

Message:
Invalid enum option provided: "Enterprise (custom)" for property 'lifecycle_stage'

Cause:
Sending a value that isn’t one of the allowed predefined options for a dropdown, single-select, or enumeration field.

Fix:

• Use the exact internal values from HubSpot.
• You can fetch them via the Properties API or check in HubSpot UI > Settings > Properties.