The Harry Potter universe spans many different mediums including books, movies, theme parks, toys, stage shows, and more.
Before all this success, and according to Business Insider, author J.K. Rowling sent her synopsis to many different publishers and was rejected 12 times!! .
Rowling posted the rejection letters on Twitter after a request from a fan. "I had nothing to lose and sometimes that makes you brave enough to try.”
Rowling received "loads" of rejections from book publishers when she first sent out her "Harry Potter and the Philosopher's Stone" manuscript. She recently tweeted that she pinned her first rejection letter to her kitchen wall because it gave her something in common with her favorite writers.
Bloomsbury finally gave book the green light in 1997. The London publishing house paid £2,500 for the manuscript: Three days after the "Harry Potter" book was published in the UK, Scholastic bid $100,000 for the American publishing rights, an unprecedented amount for a children's book at the time.
Source Story: Multiple net sources https://www.rd.com/list/ironic-failures-of-wildly-successful-people/