Per LiveMint:

Elon Musk and Twitter CEO Parag Agrawal grew close over their shared passion for engineering, recently-released text exchanges show. After learning that Musk had acquired a sizable investment in the business, Twitter gave him a seat on its board but Musk thought it would be a waste of time.

Musk told Agrawal that he had “a ton of ideas" but he thought he was “pushing too hard". Musk texted Agrawal, “I just want Twitter to be maximum amazing."

It apparently happened during the spring until the Tesla CEO tweeted in April: “Is Twitter dying?

After Musk’s “Twitter is dying" tweet, he said he would not be joining the board after all. Later, Twitter disclosed in a regulatory filing that Musk had proposed paying $44 billion to acquire Twitter outright. After initially attempting to prevent the hostile takeover, Twitter ultimately decided to accept the offer.