Issue

When an external user invited to a Box folder logs in via a web browser, the following error message may appear: “Oops! We can't seem to find the page you're looking for.” As a result, the user is unable to access the shared folder or their account settings.

Root Cause

This issue is typically caused by a problem with the invited external user’s "two-factor authentication (2FA)" configuration.

Specifically, 2FA is enabled for the user but the user does not receive the authentication code correctly (or the code is not entered). Under this situation, the login process remains incomplete. In network capture logs, a 400 Bad Request error may be recorded for requests related to Multi factor auth. As a result, the authentication process fails and the standard Box interface does not load, while an error page appears instead.

Resolution

Step 1: Verify the Issue Using Network Capture (Diagnostics Step)

First, confirm whether the issue is related to 2FA.

1. Use the browser’s developer tools to capture network activity during login. 
   Reference: How to Generate Network Captures for Troubleshooting
2. Find requests related to Multi factor auth within the network capture to confirm whether a 400 Bad Request status code has been returned.

Step 2: Disable Two-Factor Authentication (2FA)

When the root cause has been identified, disable two-factor authentication by using one of the methods below.

• External Users: The affected user who cannot log into Box has to contact Box Support directly and request two-factor authentication be disabled.
• Managed Users: Using the "Instant Login" feature, the administrator needs to disable two-factor authentication from the user’s settings page.

Step 3: Log In Again and Reconfigure 2FA

When two-factor authentication has been disabled, the user can log in using only their password. Once the log-in process has succeeded, re-enable two-factor authentication as necessary.