According to Patrick Hannan, building inspector spokesman, permission from the California city’s planning commission and a building permit are both required in order to ensure the sign’s structural integrity and safe installation.

The department said that the necessary permissions were not given for removal of the “@twitter” letters previously found on the building, and the newly installed X sign is also a security concern.

Last week Elon Musk said that he intends to change Twitter’s logo to an “X” from the iconic and beloved blue bird.

“If a good enough X logo is posted tonight, we’ll make go live worldwide tomorrow,” said Musk, who last year bought the social media website for U$44 billion, followed by a plunge in its value, with advertisers fleeing and users complaining of controversial changes.​​​​​​​