Twitter Reportedly Blocks Google Voice Numbers From SMS Authentication

It looks like Twitter has dropped support for text message two-factor authentication (2FA) using Google Voice numbers.

According to 9To5Google(Opens in a new window), trying to confirm a virtual Google Voice number using 2FA results in an error message that says: “We cannot currently register this phone number.” And when users attempt re-add a Voice number to an account after removing it, Twitter says, “This phone number can’t be registered. Try signing in with email instead.” 

The error messages did not appear when the change was first implemented last week, with users instead left with a blank box that did not explain the error, 9To5Google reports. 

The move could lead to accounts that are authenticated using Google Voice numbers being logged out. For people logged into Twitter on another device, it’s possible to turn off “Text message” 2FA from Settings > Security and account access > Security > Two-factor authentication. 

Since taking the helm of Twitter in October, Elon Musk has been on a drive to remove bots from the platform. It’s this drive that outlets have reported is affecting text message-based 2FA. Earlier this month, The Platformer found(Opens in a new window) that the company stopped traffic from 30 mobile operators worldwide including carriers in India, Malaysia, and Indonesia. 

The decision effectively locked off hundreds of thousands of Twitter accounts that used those operators for 2FA. Before the operation Musk had tweeted(Opens in a new window) “the bots are in for a surprise tomorrow.”

After legitimate users complained of not being able to access their accounts, Twitter reversed course and unblocked traffic from the mobile operators, The Platformer reported.

In a Twitter Spaces(Opens in a new window) on Dec 20, Musk poured some light on why the move was made. During the Spaces call, he accused telephone companies in “other parts of the world” of “gaming the system” by running two-factor authentication texts on repeat and “creating a zillion bot accounts” so that Twitter would pay them “millions of dollars.”

Anyone using Gmail can set up a Google Voice number for free.