According to sources from New York magazine’s Gabriel Sherman, President Donald Trump is angry that CNN and CNN chief Jeff Zucker do not grant him the favorable type of coverage he receives from Fox News

Trump has made it no secret his contempt for CNN, recently lambasting the network’s ratings in a January 24 tweet praising Fox’s inauguration coverage.

Congratulations to @FoxNews for being number one in inauguration ratings. They were many times higher than FAKE NEWS @CNN - public is smart!

— Donald J. Trump (@realDonaldTrump) January 25, 2017

Trump’s tweet comes on the heels of his January 11 attack on CNN’s senior White House correspondent Jim Acosta, refusing to answer the journalist’s questions and calling CNN “fake news.” After the press conference, Acosta was threatened by White House press secretary Sean Spicer, who said he would remove Acosta if he treats Trump disrespectfully. The next Sunday, Trump’s team failed to appear on CNN’s Sunday news program, State of the Union, but sent representatives to MSNBC, Fox, CBS, and ABC.

Trump also attacked the network before and immediately after the election, questioning the credibility of the network, and attacking individual journalists as dumb, lightweights, who aren’t real journalists.

According to a report from Gabriel Sherman, Trump’s antipathy towards CNN may be personal.Sherman quoted one high-level CNN source as saying, “Trump thinks just because he’s known Jeff that CNN should be covering him like Fox News does”:

According to people close to both sides, Trump has told White House staffers that he feels personally betrayed by CNN chief Jeff Zucker.

Trump complains that Zucker should be programming CNN more favorably toward him because of their long relationship, which can be traced back to 2004 when Zucker put The Apprentice on NBC. Trump has also said to White House staffers that Zucker owes him because Trump helped get him the job at CNN.

According to CNN sources, Trump’s claim that he assisted Zucker in landing the top job at the network is false. Trump seems to have gotten the idea because he praised Zucker to Turner Broadcasting’s then-CEO Phil Kent at a charity dinner in the fall of 2012, a few months before CNN hired Zucker. But CNN sources say Turner had already decided to hire Zucker by that point. “This is entirely personal,” one CNN high-level source said. “Trump thinks just because he’s known Jeff that CNN should be covering him like Fox News does.”