Enhanced antifraud of sites detects open ports of residential proxies (socks5) and blocks access to accounts or rejects card payments.
Another possible reason for blocking is a dirty IP address (the set page load limit has been exhausted, it is blacklisted, it is in a fraudulent database or spam block). Before working, be sure to check the cleanliness of the IP address.
Solution: Change the proxy provider or do not use a proxy if you have any device running on iOS.