[Python] Why does Spotify return {"error":"errorUnknown"} when submitting login credentials...

I'm trying to programmatically log into Spotify using Python, with the help of Playwright and a ReCaptcha V3 bypass solution (go-recaptcha-v3-bypass or 2Captcha). I extract the correct flow_ctx and cookies via Playwright, solve the ReCaptcha, and then attempt to log in using requests.post.

Despite providing what appears to be all valid data — correct headers, cookies, CSRF token, recaptchaToken, and flow_ctx — Spotify responds with a 400 Bad Request and this JSON:

{"error":"errorUnknown"}

This doesn't happen in the browser with the exact same credentials. It only happens with requests.

Here's my code:

import requests
from urllib.parse import quote
from playwright.sync_api import sync_playwright
from pypasser import reCaptchaV3

EMAIL = ""
PASSWORD = ""
UA = "Mozilla/5.0 (Linux; Android 6.0; Nexus 5 Build/MRA58N) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Mobile Safari/537.36"

def get_anchor_flowctx_and_cookies():
with sync_playwright() as p:
browser = p.chromium.launch(headless=False)
context = browser.new_context(user_agent=UA)
page = context.new_page()
page.goto("https://accounts.spotify.com/en/login", wait_until="networkidle")

anchor_url = ""
for frame in page.frames:
if "recaptcha/enterprise/anchor" in frame.url:
anchor_url = frame.url
break
if not anchor_url:
raise RuntimeError("Anchor URL not found")

flowctx = page.eval_on_selector("meta#bootstrap-data", """el => {
try {
const raw = el.getAttribute("sp-bootstrap-data").replace(/"/g, '"');
const parsed = JSON.parse(raw);
return parsed.flowCtx;
} catch (e) {
return null;
}
}""")
if not flowctx:
raise RuntimeError("flowCtx not found")

# Забираем куки из контекста
cookies = context.cookies()
cookie_dict = {cookie["name"]: cookie["value"] for cookie in cookies if ".spotify.com" in cookie["domain"]}

browser.close()
return anchor_url, flowctx, cookie_dict

def bypass_recaptcha(anchor_url: str) -> str:
return reCaptchaV3(anchor_url)

def spotify_login(email, password, token, flow_ctx, cookie_dict):
session = requests.Session()

for name, value in cookie_dict.items():
session.cookies.set(name, value, domain=".spotify.com")


session.cookies.set("remember", email, domain=".spotify.com")
print(session.cookies)
csrf = cookie_dict.get("sp_sso_csrf_token")
if not csrf:
raise RuntimeError("CSRF token not found")

data = {
"username": email,
"password": password,
"continue": f"https%3A%2F%2Fopen.spotify.com%2F%3Fflow_ctx%3D{flow_ctx}",
"recaptchaToken": token,
"flow_ctx": flow_ctx,
}
headers = {
"User-Agent": UA,
"Content-Type": "application/x-www-form-urlencoded",
"X-Csrf-Token": csrf,
"Origin": "https://accounts.spotify.com",
"Referer": f"https://accounts.spotify.com/en/login?flow_ctx={quote(flow_ctx)}",
}

resp = session.post("https://accounts.spotify.com/login/password", data=data, headers=headers)
return resp.text, resp.status_code

if __name__ == "__main__":

anchor_url, flow_ctx, cookie_dict = get_anchor_flowctx_and_cookies()
print("✅ anchor:", anchor_url)
print("✅ flowCtx:", flow_ctx)


token = bypass_recaptcha(anchor_url)
print("✅ recaptchaToken:", token)

result, code = spotify_login(EMAIL, PASSWORD, token, flow_ctx, cookie_dict)
print(result)
print(code)

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