Error: 400 Bad Request - subscriber_id cannot be blank (2)

What are you trying to achieve?

I´m trying to make a HTTP Request to Manychat for Set Custom Field but I´m having this problem:

DataError
Error: 400 Bad Request
{“status”:“error”,“message”:“Validation error”,“details”:{“messages”:[{“message”:“subscriber_id cannot be blank.”}]}}

I checked every aspect of subscriber ID, and even tried to replace it with an existing value, but the problem remains.

Here is my HTTP request body:

Check if you need quotes around subscriber ID.