Disgraced political pundit Mark Halperin was very unhappy when MSNBC brass nixed his attempt to repair his career through a possible collaboration with the stars of Morning Joe. So he picked up the phone and called network chief Phil Griffin.

It did not go well.

Multiple sources tell The Daily Beast that the conversation earlier this year became acrimonious, with Halperin dishing up vague threats against his former boss.

MSNBC declined to comment on the episode. But MSNBC insiders said Griffin was furious about the conversation and wouldn’t likely take Halperin’s calls in the future.

The hostile exchange was a sign of Halperin’s frustration that his dream of returning to the punditry business—almost two years after numerous women came forward with stories of sexual misconduct—has been thwarted at each turn.

The former MSNBC contributor has been attempting to rehab a career that imploded when former colleagues and subordinates accused him of groping and unwanted sexual advances during his tenure as an ABC News political reporter.

After months of silence, Halperin began dipping back into the public eye. Earlier this year, he launched a politics blog called “Mark Halperin’s Wide World of News,” appeared on national radio interviews, and authored a new political book set for release this fall.

The Game Change author has privately told friends that he wants to return to cable news, and he has lobbied various media outlets for a second chance. The Daily Beast reported earlier this year that, according to sources, Halperin called the top editor at D.C.-based political newspaper The Hill to inquire about job prospects but was rebuffed.

And then when Halperin’s former pals Joe Scarborough and Mika Brzezinski sought to collaborate with him on an online-only MSNBC broadcast analyzing the 2018 midterm elections, the entire plan was eventually scuttled. The failed scheme caused consternation within the building—“Everybody was going ‘WTF!,’” one MSNBC insider told The Daily Beast—and ultimately led to Halperin’s hostile call with Griffin. (Brzezinski later told Yahoo News of Halperin: “I don’t expect him back on our show... he’s on his own in terms of his next act.”)

Not only has Halperin’s career revival been curbed by his own ex-employer, it’s been poorly received by the public at large.

A number of Democratic analysts who spoke to Halperin on the record for his upcoming book expressed regret for participating in the project following outrage from critics and the women who accused him of misconduct.

And the cast of Morning Joe faced serious backlash for boosting Halperin’s rehab tour on-air earlier this year by dedicating a segment to his apologetic interview with SiriusXM radio host Michael Smerconish and positively commenting on his words. Sources told The Daily Beast at the time that network executives were unaware the show planned to address the sensitive Halperin topic and were unhappy with the decision.

When Smerconish, who also hosts a CNN weekend program, once again invited Halperin on his SiriusXM daytime talk show last week, a top CNN spokesperson expressed disbelief on Twitter. “You’ve got to be kidding me,” wrote Matt Dornic, the network’s vice president of communications.

Halperin has repeatedly expressed remorse for his actions, telling The Daily Beast last year that he was “deeply sorry and hope to have a chance to apologize directly to those I treated badly. It is the right and necessary thing to do.”

But he has also taken not-so-subtle swipes at his critics, seeming to question their sincerity.

“I wasn’t a perfect person when I made these mistakes,” he told Smerconish during his interview on Sirius XM earlier this year. “I’m not a perfect person now. I’m happy to be judged by perfect people.”