From Wikipedia
“After the publication of his book The Dignity of Difference, a group of Haredi rabbis, most notably Rabbis Yosef Shalom Elyashiv and Bezalel Rakow, accused Sacks of heresy against traditional Orthodox viewpoint. According to them, some words seemed to imply an endorsement of pure relativism between religions, and that Judaism is not the sole true religion, e.g. “No one creed has a monopoly on spiritual truth”. This led him to rephrase more clearly some sentences in the book for its second edition, though he refused to recall books already in the stores.[13]”
On a personal note, I think highly of him and read his articles frequently.