Unable to complete Facebook Messenger connection despite successful login and 2FA

[piknockyou]

Description:

The Facebook Messenger connection consistently fails on both Windows and Android after completing a multi-step authentication process. The login on Facebook's side appears successful (including 2FA), but Beeper fails to establish the final connection, resulting in an error. This behavior is consistent across platforms, suggesting an issue with how Beeper handles the final authentication token from Facebook.

Steps to Reproduce (Observed on both Windows & Android):

1. In the Beeper app, initiate the process to add a Facebook Messenger account.
2. At the first Facebook login prompt, enter credentials and log in.
3. After the first login, the page reloads, requiring a second login. Enter credentials again.
4. At the Facebook 2FA prompt, enter the verification code.
5. The 2FA is accepted, and the authentication flow returns to the Beeper app.
6. Beeper attempts to connect but ultimately fails, displaying the error: "Error starting your connection [...]"

Cookie Notice Behavior During Login:

A cookie consent notice is presented at each of the three authentication stages (first login, second login, and 2FA). The behavior differs by platform:

• On Windows: All three cookie notices are automatically dismissed without user interaction.
• On Android: The first and third notices are manually accepted. The second notice (at the repeated login prompt) is automatically dismissed.

Workarounds Attempted (All Failed):

I have attempted the following standard troubleshooting steps without success:

1. Fresh Connection: Removed the Facebook Messenger connection from Beeper and attempted a fresh login.
2. Full App Reset: Cleared all Beeper app data on Android, restored the account via recovery key, and then attempted a fresh login to Facebook Messenger.
3. Password Reset & Logout: Changed my Facebook password and used the "Log out of all other devices" option. This also failed, but it altered the login flow slightly: instead of two Facebook logins, it prompted for one Facebook login and then one Messenger login before the 2FA step.

Conclusion:

The authentication process requires two consecutive logins and one 2FA verification. Despite successfully passing all of Facebook's authentication steps and attempting all common workarounds, Beeper is unable to finalize the connection.

Further evidence of a successful login on Facebook's end comes from the security alert emails received immediately after each attempt:

Security alert: login near [Location] on a new device

Hi [Username],

Someone just logged in to your Facebook account near [Location] on Chrome on Linux. If this wasn't you, we're here to help you take some simple steps to secure your account.

Was this you?

Environment:

• Platforms: Windows Desktop v4.0.779, Android v4.27.1
• Account Type: Facebook Messenger with 2FA enabled

[cameronaaron]

Is this happening with the beeper hosted ones as well? Have you tried again recently from scratch?

[piknockyou]

Is this happening with the beeper hosted ones as well? Have you tried again recently from scratch?

Working again since a week.