When acquiring global IP, an error shows "Quota for public_ip exceeded".

Customers can subscribe global IP addresses based on the following subnet mask. The maximum number of subnet mask that Customers can subscribe per Tenant is 4.
The error "Quota for public_ip exceeded" may be caused by this restriction.
In order to resolve the error, after deleting the global IP, you need to expand and reacquire the address range.

Reference: Service Descriptions - Internet Connectivity - Important Notes of Subscription