Twitter announced Friday that users who do not subscribe to Twitter Blue will soon have to give up using text messages as a two-factor authentication method to secure their accounts.

The social media platform, which was acquired by billionaire Tesla founder Elon Musk last year, informed its users about the new policy in a press release Wednesday, saying that it will no longer permit non-Twitter Blue subscribers to use text messages as a two-factor authentication method after March 20. 

Two-factor authentication is a tool which requires users to enter a security code or key — in addition to their normal password — in order to gain access to their accounts.

“This additional step helps make sure that you, and only you, can access your account,” Twitter said about the process.

The company said the change is the result of “bad actors” abusing the phone number two-factor authentication system.

Any users who do not subscribe to Twitter Blue, and still have the two-factor authentication by text enabled, will lose access to the service on March 20 if they do not opt out on their own.

In addition to text message, Twitter offers two other methods of two-factor authentication: an authentication app and a security key. Those two methods will remain free and available options for non-Twitter Blue members who still want to employ an extra security measure for their accounts.

“Use of free authentication apps for 2FA will remain free and are much more secure than SMS,” Musk tweeted Saturday.