You can encounter this issue if you use an outdated Enterprise version of our server software or your attached CC has insufficient funds / not valid / exceeded Internet payments limit. Please check the attached error below for reference.
The “Billing” section for updating billing details is available only for Cloud server customers, while Enterprise customers have to update billing details on a separate billing page: QuickBlox Billing
Feel free to check our official documentation for more information that will help you to integrate QuickBlox services into your applications / projects or contact our Support team by submitting a ticket if you have any other questions.