As House lawmakers move quickly toward a likely impeachment vote before the year’s end, President Donald Trump has kept a close eye on his conservative media allies—and hasn’t been shy about trashing them for projecting insufficient fealty.

But it’s been one media outlet in particular that has caught the president’s ire, even though it has so far been spared his Twitter rage: the Drudge Report. Publicly, Trump hasn’t said a peep about the highly popular news aggregator run by right-wing media impresario Matt Drudge. But privately, he has simmered over the critical coverage that the site has run and linked to, with regards to the impeachment proceedings.

“What’s going on with Drudge?” Trump has been asking allies since Democratic lawmakers launched the impeachment probe in late September, according to a person with knowledge of his private remarks. Two other sources who’ve heard the president complain told The Daily Beast that Trump has asked those close to him why they think Drudge and his website have seemed “so anti-Trump” lately.

In recent weeks, Trump has even asked Jared Kushner, his son-in-law and a top White House official—who has had a friendly relationship with the site’s creator—to “look into it” and reach out to Drudge, the sources said.

It is unclear if Kushner has done so. The White House and Drudge did not respond to requests for comment on this story as of press time.

The president’s concern over Drudge’s coverage of the impeachment proceedings underscores how sensitive he has been to ensuring that his fellow travelers, in Republican politics and in influential media, do not break from him as Democrats take steps to remove him from office over the Ukraine scandal.

Trump has repeatedly complained in the past couple months that Senate Republicans, who will have to vote on whether or not to acquit him, haven’t been doing enough to protect him, and has made moves to quietly secure individual senators’ support. This past week, the president went after the largely Trump-aligned Fox News for hosting certain pro-impeachment voices—“Losers!” he said—on the air. The network, Trump insisted, should instead be sticking with “the people that got them there.”

But Drudge’s alliance is a different matter entirely. Due to its huge audience, the site wields massive influence not just in conservative media, but in driving media narratives and political conversation among legacy newspapers and mainstream media publications as well. It’s so well read that even Hillary Clinton’s 2008 campaign attempted to forge a relationship with Drudge to try to pacify him from efforts to destroy her presidential bid. (The irony in it all was that the Drudge Report rocketed to prominence by breaking news of her husband’s White House sex scandal.)

Trump’s private fretting over “what’s going on” at the Drudge Report isn’t an isolated concern. Numerous others in the president’s orbit—re-election campaign, West Wing, media circles, long-time friends and associates—have noticed the site’s drift, as well. Some have expressed their anxieties about it directly to the president.

For most of the Trump era, the widely read conservative aggregator has served as a bastion of pro-Trump content and headlines. But for months, Trump fans have alleged that the tone of the coverage at the website has taken a sharp turn, even to the point of tacitly supporting the Democratic impeachment drive and disregarding Republican arguments.

“The Drudge Report is my favorite website,” Jesse Watters, a Fox News host and pal of the president, said on-air early this month, before highlighting the recent negative Trump stories that have dotted the site. “You know, that’s what you log on to CNN.com for… It just seems like the website has recently played up Trump gaffes and downplayed his successes.”

The fact that the president himself hasn’t yet taken to Twitter to bash Drudge in recent weeks may also have something to do with his general assessment of— and, at times, begrudging respect for—how Drudge operates, according to people who’ve spoken to Trump about the website and its famously reclusive creator.

“[Trump] understands his influence; knows he can be a little mercurial, though, and prone to stir the pot,” said a former senior White House official. “He also knows Drudge isn’t able to be bullied. [Matt] doesn’t owe his career to anyone…[and] can’t be moved the way others can because he’s not afraid—not just of Trump but in general.”

Through it all, the president remains an avid Drudge reader. But since Trump doesn’t regularly visit or browse websites on a computer himself, he relies heavily on White House staff to include printouts of Drudge headlines and the homepage in his daily packages of printed articles and media clips.

In the past three weeks, one White House source recalled seeing the president flipping through a stack of papers, mostly made up of news articles involving the impeachment process. At one point, he got to a page of Drudge headlines. Trump, the source said, began scrutinizing the page, and started “making [grumpy] noises that made his feelings clear.”