Why Am I getting '400 Proxy Error: ip_requested_not_allocated_by_customer' ?

When Using the Data center/ISP or Gips products, the error code 400 can appear in case the IPs under your zone has been refreshed, removed, or simply changed due to system updates
Whenever this error appear, you should go to your Bright Data Zones page , and Download the new list of IPs relevant to this zone.
Make sure you also update the list of IPs in case you are using the proxy manager tool with prefix of IP<>port setup

example:
curl --proxy brd.superproxy.io:22225 --proxy-user brd-customer-c_c178f564-zone-isp-ip-1.1.1.1:Password "http://lumtest.com/myip.json" -v