Twitter will reserve text-message authentication for Twitter Blue subscribers because it's being 'abused' by 'bad actors'

• Twitter said only Twitter Blue subscribers can use text messages to secure accounts from March 20.
• Text message two-factor authentication was being "abused" by "bad actors," the company said.
• A Twitter Blue subscription costs $11 a month on Android or iOS. 

Twitter is restricting the use of text messages for two-factor authentication to paying Twitter Blue subscribers, the company announced on Friday.