SAN FRANCISCO (AP) — Celebrities and other high-profile Twitter users are once again being verified by the social media platform and they don't know why the blue check marks reappeared — nor do they seem too happy about it.

Twitter removed the blue marks last week from accounts that don't pay a monthly fee. But the check marks mysteriously returned for many highly followed accounts over the weekend, leading some prominent users to disavow what's become a divisive symbol of Twitter owner Elon Musk's erratic changes to the platform.

Accounts belonging to the Massachusetts Institute of Technology, Bette Midler, gymnast Simone Biles Owens, writer Neil Gaiman and rapper Lil Nas X were among the users — all with more than 1 million followers — who took to Twitter to make clear they didn't pay to get their blue check back.

"On my soul i didn't pay for twitter blue, u will feel my wrath tesla man!" wrote the rapper who has 8 million followers. Added Gaiman, who has 3 million followers: "What a sad, muddled place this has become."

Midler said Sunday: "Yes, Elon gave me back my blue check but I didn't pay for it. Does that make me a good guy or a bad guy? I'm so confused." But by Monday, there was no sign she had a blue check.

Twitter had roughly 400,000 verified users under the original blue-check system, including Hollywood actors and star athletes but also journalists, human rights activists and public agencies. In the past, the checks meant that Twitter had verified that users were who they said they were, as a method to prevent impersonation and the spread of misinformation.

But now anyone can buy a Twitter Blue subscription starting at $8 a month. It no longer means the user is verified — other than confirming a phone number — but promises a number of features including the ability to have more people see their tweets.

Musk has pushed for the premium service as a way to increase revenue and upend a "lords & peasants system" he believes gave too many people an undeserved status symbol for free. But only a fraction of users — and very few of those who had the blue checks before — are buying the service.

An inability to sell subscriptions or find other ways of making money could present problems for Musk, who bought Twitter for $44 billion last year and has struggled to keep advertisers — its main source of revenue — from fleeing the platform.