This article originally appeared on ABACUS Work collaboration and note-taking app Notion is no longer accessible in China, according to its San Francisco-based owner. “Notion is blocked by a firewall in China. We are monitoring the situation and will continue to post updates,” the company said in a tweet posted Sunday evening local time . Notion’s app lets anyone from individual users to entire workplaces and classrooms organize digital documents, take notes, set up to-do lists and team up with each other. Founded in 2013, Notion currently serves about 4 million users of both its paid and free tiers in more than 20 countries worldwide, the startup told the New York Times last month. Some of these users are apparently located in China, where Weibo users vented their disappointment about the app’s blockage on Monday. “Arrived at work this morning to find Notion blocked by the Great Firewall,” one user wrote . “What can I say, maybe people in China don’t deserve any of the good things available on the normal internet.” The story of China’s Great Firewall, the world’s most sophisticated censorship system “Notion has been firewalled, not sure if things will be better after the victory meeting,” another wrote , referring to China’s annual legislative session known as the Two Sessions currently taking place in Beijing. Authorities have regularly tightened internet censorship during important political gatherings, at times restricting the use of VPN services. We reached out to Notion with questions about their plans for users in China and will update the story if we hear back. Notion isn’t the first foreign workplace app impacted by the Great Firewall. Last September, the international version of the US video-conferencing app Zoom was suddenly blocked in China , forcing users to move to a localized version that was franchised to operators in the country. Notably, Notion competitor Evernote remains available even though it's previously been used to circumvent censorship . The company launched a local version called Yinxiang Biji in 2013, which was spun off into a joint venture in 2018. While Evernote.com forwards users in China to Yinxiang, foreign Evernote accounts are also accessible. Yinxiang has also been anticipating competition from Notion, as evidenced earlier this month when it was revealed that the company registered for Notion’s trademark and logo in China last year.