Even great novelists occasionally write a clunker -- sort of a loose cannon in a canon.
Often, the literary dud comes at or near the start of an author's career. For instance, Jack London's A Daughter of the Snows (1902) deserves kudos for starring a strong female character, but it's an awkward novel with stilted dialogue. Maybe London had to write it to get the hang of that fiction-book thing, because he quickly penned the amazing dog adventure The Call of the Wild (1903) and the superb nautical thriller The Sea-Wolf (1904).
Then there are the book fails that come at or near the end of an author's career. One example is Willa Cather's Sapphira and the Slave Girl (1940). Cather's 11 previous novels (published between 1912 and 1935) ranged from very good (O Pioneers! and Shadows on the Rock) to sublime (My Antonia and Death Comes for the Archbishop), but Sapphira is nearly unreadable. Cather was dealing with ill-health and perhaps some depression during the last decade of her life, so that undoubtedly affected her writing.
But some renowned authors received cash for clunkers during the height of their careers. For instance, Carson McCullers wrote the exquisite The Heart Is a Lonely Hunter and the stunning Reflections in a Golden Eye before coming out with her mostly tedious The Member of the Wedding. That last book has its moments and its admirers, but all I recall is being left at the altar of boredom.
John Steinbeck wrote books such as the masterful The Grapes of Wrath, the mesmerizing East of Eden, the delightful Tortilla Flat, and the late-career gem The Winter of Our Discontent. But he also authored the mid-career dud Burning Bright. It's an over-stylized novella about a guy upset that he can't father a child, and Steinbeck weirdly has him be a circus member in the book's first part, a farmer in the book's second part, etc., without time passing to switch professions. Maybe he's supposed to be an "everyman." Also, no Burning Bright characters talk like real human beings -- but at least they don't speak to a dad-who's-allegedly-now-a-tree like Joseph Wayne does in Steinbeck's To a God Unknown.
The dialogue almost always rings true in Stephen King's page-turning novels, but not so much in Cell. Even the plot machinery in that apocalyptic book grinds and wheezes, which is surprising for a marvelous author like King. Cell, though intermittently exciting, is one of King's very rare missteps.
Speaking of missteps, how about that supremely dopey sequel Tom Sawyer, Detective? Well, Mark Twain needed the money at the time.
If you'd like to mention any other book blunders by famous authors, or if you disagree with any of my dud determinations, I'm sure none of your comments below will be clunkers!