Authentication issues may include inability to log in, unexpected logouts, or errors while using other authentication methods. You might see license-related errors if you cannot connect to the WHMCS license server or there is a misconfiguration in your system. Two-Factor Authentication (2FA) enhances security by requiring both a password and a second step like a login code from a mobile device. Duo® Security is a two-factor authentication (2FA) option that combines traditional account credentials with device-based verification. Initiate a password reset for a user who has lost their Client Area password. Users can also initiate password resets on the login form. API authentication credentials allow your API-connected devices and systems to authenticate with WHMCS using API roles that you create. Single Sign-On allows users to log in to a cPanel & WHM or Plesk hosting account directly from a link in WHMCS without reauthenticating. Application Links use WHMCS Single Sign-On to allow users to seamlessly access WHMCS from the cPanel or WP Squared control panels. Sign-in integrations allow customers to connect with our supported platforms — Facebook®, Google®, or X™ (formerly Twitter™) — to quickly sign up or log in to WHMCS. OpenID Connect is the online standard for Single Sign-On and identity provisioning. It uses JSON-based identity tokens (JWT) and OAuth 2.0. OpenID Connect uses JSON-based identity tokens (JWT) and OAuth 2.0 to allow third-party applications to access WHMCS with Single Sign-On. Troubleshoot and resolve warnings about CloudFlare® trusted proxies. Troubleshoot and resolve issues with frequent logouts. Troubleshoot and resolve Your license key is invalid errors in the API. Troubleshoot and resolve License Invalid errors. Troubleshoot and resolve Login Details Incorrect errors. Troubleshoot and resolve issues with sessions not being removed. You can adjust the login session length for admins and users. WHMCS will automatically end login sessions after the set period of inactivity. Troubleshoot and resolve No Connection licensing errors. Troubleshoot and resolve Oops! Access Denied - Forbidden errors while logging in to WHMCS.