The Auth failed (also appears as 407 status code) within the "ip_forbidden" text message can happen when your proxy zone is configured with Whitelist IPs permission, and the machine IP (crawler) is not part of that list.
In order to resolve this matter, you can either use the API doc or do it manually from your zones
Please Note - Bright data use active blacklist for suspected activities in case the zone is not set with whitelist IPs permission
Read more about blacklist IPs
Another solution can be implemented by using the Proxy manager tool as your entry point
which will guarantee fixed IP