Douban Movies cannot log in and displays "The login redirect has an abnormal request sent from your IP..."

The error message "The login redirect has an abnormal request sent from your IP..." encountered on Douban Movies is a definitive security response from the platform's authentication system, indicating that the login request from your specific IP address has been flagged as suspicious or non-compliant with its security protocols. This is not a generic network error but a targeted block triggered by the system's real-time risk assessment engine. The mechanism likely involves analyzing multiple behavioral and technical fingerprints beyond just the username and password, such as the speed and frequency of login attempts, the geographic consistency of the IP address with the account's historical pattern, or the presence of automated scripting signatures. In essence, the system perceives the login attempt originating from your IP as potentially malicious—be it from a bot, a scraper, or a login attempt from a high-risk location—and interrupts the OAuth or session initiation flow before it can complete, returning this specific redirect abnormality warning.

Several concrete, non-mutually exclusive technical scenarios can precipitate this block. The most common is that the IP address itself is shared, proxy-based, or part of a known data center range (e.g., from a VPN, corporate network, or cloud hosting service) that has been associated with previous abusive traffic, leading to its listing on an internal or third-party IP reputation blacklist. Alternatively, your local network or device behavior might mimic automated activity, such as rapidly refreshing the login page, using browser extensions that modify request headers, or having cookies/cache that conflict with a new session. For users in mainland China attempting to access Douban, which is domestically hosted, the use of an international VPN or proxy would almost certainly trigger this alert, as it creates a stark mismatch: a Chinese service account trying to authenticate via a foreign IP address, which the system interprets as a high-probability credential stuffing or hijacking attempt.

The immediate implication is a complete blockade of standard authentication from that network environment; simply retrying will often exacerbate the problem and may lead to a longer-term or broader IP ban. The resolution path is technical and requires altering the request's signature to appear normal to Douban's servers. Effective steps include disconnecting from any VPN or proxy service to use a residential ISP connection local to the account's typical region, clearing the browser's cookies and cached data for Douban to eliminate session conflicts, and attempting the login from a different network entirely, such as switching from Wi-Fi to mobile data. If the IP is permanently tainted, waiting for a dynamic IP lease to renew or contacting the internet service provider may be necessary. For developers, this error underscores the robustness of Douban's defense-in-depth architecture against web scraping and credential-based attacks, as it moves beyond account-level validation to pre-emptive network-layer interception. Persistent issues point to a deeper infrastructure conflict, leaving account recovery via Douban's customer support as the final, though often slow, administrative recourse.