Python requests ProxyError: Cannot connect to proxy, every cause

import os

import requests

USER = os.environ["PROXY_USER"]
PASS = os.environ["PROXY_PASS"]
proxy = f"http://{USER}:{PASS}@via.proxies.vision:9000"

try:
    r = requests.get("https://ipinfo.io/ip", proxies={"http": proxy, "https": proxy}, timeout=30)
    print(r.status_code, r.text.strip())
except requests.exceptions.ProxyError as e:
    cause = e.args[0].reason.original_error  # the exception urllib3 wrapped
    print(type(cause).__name__, "-", cause)

import os
import time

import requests

USER = os.environ["PROXY_USER"]
PASS = os.environ["PROXY_PASS"]
proxy = f"http://{USER}:{PASS}@via.proxies.vision:9000"
proxies = {"http": proxy, "https": proxy}


def get(url: str, attempts: int = 3) -> requests.Response:
    for attempt in range(attempts):
        try:
            return requests.get(url, proxies=proxies, timeout=30)
        except requests.exceptions.ProxyError:
            raise  # the proxy refused or is unreachable: retrying won't help
        except (requests.exceptions.SSLError, requests.exceptions.ConnectionError,
                requests.exceptions.Timeout):
            if attempt == attempts - 1:
                raise
            time.sleep(attempt + 1)  # a dropped exit: the next request gets another one


print(get("https://ipinfo.io/ip").text.strip())