New Delhi, Apr 12 (IANS): Elon Musk on Thursday gave another deadline of April 20 to remove all legacy Blue check marks, after faltering on the first deadline of April 1 due to lack of the backend technology to achieve this.

According to reports, there were technical challenges to removing so-called blue ticks quickly at scale and the only way to do it currently was a manual approach.

Musk said in a tweet that "Final date for removing legacy Blue checks is 4/20".

Details earlier emerged that Musk-run company does not have the backend technology to remove around 4.2 lakh legacy accounts with Blue ticks all at once.

"Removal of verification badges is a largely manual process powered by a system prone to breaking, which draws on a large internal database -- similar to an Excel spreadsheet -- in which verification data is stored, according to the former employees," according to The Washington Post.

"In the past, there was no way to reliably remove badges at a bulk scale -- prompting workers tackling spam, for example, to have to remove check marks one-by-one. It was all held together with duct tape," it added, quoting a former employee.

Musk had earlier given a deadline of April 1 to remove all legacy accounts with Blue verification. The company has so far only removed the Blue tick for The New York Times.

Twitter launched its verification system in 2009 to protect celebrities from impersonation but now, Musk wants everyone to pay $8 a month for the Blue badge.

The White House and The New York Times refused to pay for verified Blue with subscription service.

LeBron James, the highest-paid NBA player of all time and earning over $40 million per year, also refused to pay Twitter.