When Juniper executives called an all-hands meeting in November, few employees expected the bombshell announcement that after just 10 months at the company, CEO Shaygan Kheradpir was out.

Kheradpir's tenure had been marked by cost cutting, restructuring, and layoffs that reportedly left Juniper's engineering staff embittered. At the all-hands, when Juniper veteran Rami Rahim was named as Kheradpir's replacement, employees responded with a standing ovation.

Juniper's public explanation of the abrupt change has been limited to a statement noting Kheradpir resigned after Juniper's board reviewed “his leadership and his conduct in connection with a particular negotiation with a customer.” Sources have now come out with some specifics.

Kheradpir joined Juniper on Jan. 1 from Barclays, where he was CTO and COO; he'd also been CIO and CTO at Verizon. Juniper touted that pedigree, and with good reason — Verizon had, at times, been the company's largest customer, and Barclays was representative of the large enterprises Juniper had been wooing in recent years.

But guess which two customers Kheradpir couldn't land?

Negotiations with both Barclays and Verizon failed, according to sources with knowledge of the matter. Verizon was the last straw for Juniper's board, those sources say, leading directly to Kheradpir's departure.

(Kheradpir did not respond to emails and phone calls requesting comment. But we'll point out that Juniper's announcement of his resignation takes the unusual step of specifying that "the Board and Mr. Kheradpir have different perspectives regarding these matters.")

In both cases, sources believe Kheradpir's personality got in the way. He was hired with an understanding that he could seal the Barclays deal, one source says. But Barclays executives thought Kheradpir came to the table with too "crude" an approach, according to the source, who adds that Barclays perceived the CEO projecting a "sense of entitlement."

In the end, we're told that Barclays went with Arista instead. Arista and Juniper declined to comment, and Barclays did not respond to request for comment.

Barclays would have been a nice account to get, certainly, but Verizon represents an especially cherished relationship. Juniper's heritage is in selling to service providers, and Verizon accounts for about 10 percent of Juniper's sales, according to Goldman Sachs. It's a customer Juniper would fight tooth and nail to keep, but it was another customer that Kheradpir alienated, sources say.

"Straighten him out, or we walk," Verizon executives told Juniper's board, as paraphrased by a source familiar with the discussions. Another source says Verizon executives declared they would never take another call from Kheradpir. A Verizon spokeswoman declined to comment.

At that point, Juniper's board reportedly decided the CEO had to go. (One Juniper board member declined to speak on the record; others did not return messages requesting comment.)

An SEC filing shows Kheradpir resigned on Sunday, Nov. 9. Juniper made the announcement to the world after the markets closed the next day.

What a difference a year makes. In February 2014, Kheradpir impressed industry analysts at an intimate get-to-know-you dinner in Barcelona the night before Mobile World Congress opened. His strategy to emphasize "high-IQ" networks and shore up Juniper's traditional service-provider market got high marks from pundits.

But Kheradpir was reportedly loathed by Juniper's engineering staff. Whether the ire was deserved is debatable. The layoffs, the cost cutting, even the predictable sale of the Junos Pulse product line — these might all have been inevitable, given Juniper's situation and the pressure coming from activist shareholder Elliot Management.

New CEO Rahim has said he's going to stick to the course Kheradpir laid out. As a 17-year company veteran, he has the potential advantage of being a familiar face to Juniper's staff and customers — and he'll likely try to bring some finesse to the negotiating table.

(Photo: Shaygan Kheradpir (left) at the 2013 StartUp Europe Forum, courtesy of Lisbon Council.  CC 2.0 license.)