President Trump, Vice President Mike Pence, and other members of the White House will meet with executives from the biggest tech companies on Monday to discuss modernizing the government.

And out of the nearly 20 companies scheduled to attend, one glaring absence is Facebook.

Neither CEO Mark Zuckerberg nor COO Sheryl Sandberg will be at the meeting, a Facebook spokesperson confirmed to Business Insider, citing scheduling conflicts as the reason why.

Earlier Zuckerberg has publicly expressed his anger against President Trump’s Policies , especially the immigration policies

“Like many of you, I’m concerned about the impact of the recent executive orders signed by President Trump,” Zuckerberg wrote on Facebook in January after Trump’s first Muslim ban. “We…make all Americans less safe by diverting resources, while millions of undocumented folks who don’t pose a threat will live in fear of deportation.”

Sandberg’s absence makes sense given that the biggest advertising festival in the world, Cannes Lions, is currently underway in the south of France. But Zuckerberg’s absence is more notable, especially given that he also skipped Trump’s last meeting with tech executives in December.

Zuckerberg is scheduled to speak at a Facebook event in Chicago on Thursday, so there’s a chance he’s busy preparing for that. He’s also spoken with Trump multiple times by phone since the election,

Facebook board member and Trump advisor Peter Thiel will also be in attendance, representing his investment firm Founders Fund.

Even still, it’s odd for Zuckerberg, a tech expert and billionaire philanthropist, to not be in the room for a meeting about how the government can bring its technical chops into the 21st century. The group will also discuss Trump’s planned overhaul of the country’s visa program for highly-skilled workers, which Facebook and other tech companies rely heavily upon to hire employees.

Here’s the full list of tech executives scheduled to meet with the White House on Monday:

Ajay Banga, CEO of MasterCard
Jeff Bezos, CEO of Amazon
Zachary Bookman, CEO of OpenGov
Safra Catz, Co-Chief Executive of Oracle
Tim Cook, CEO of Apple
John Doerr, Chairman of Kleiner Perkins
Pat Gelsinger, CEO of VMware
Alex Karp, CEO of Palantir
Brian Krzanich, CEO of Intel
Tom Leighton, CEO of Akamai
Bill McDermott, CEO of SAP
Steven Mollenkopf, CEO of Qualcomm
Satya Nadella, CEO of Microsoft
Shantanu Narayen, CEO of Adobe
Ginni Rometty, CEO of IBM
Eric Schmidt, Executive Chairman of Alphabet
Julie Sweet, CEO of Accenture
Peter Thiel, Founders Fund