Advance payment customer

I have activated the credit check limit for the Advance payment customer.

The customer has a 72000 advance amount. The sales order value is 10500.

The customer has the advance amount also, there is no open sales order for the customer. While I am trying to do delivery its shows as "Order blocked for delivery as a result of credit check"

Please guide me to resolve the issue.

Thanks in advance.

Breetha K