It looks like Slack, the $7 billion chat app, is banning some users because of Iran sanctions - even if they don't live or work in Iran

• Ethnically Iranian users and users who have traveled to Iran found out Wednesday that their Slack accounts had been shut down.
• Slack identified those users' accounts as being from Iran, which has been sanctioned, based on IP addresses.
• However, many of these users do not actually live in Iran, nor do they have professional ties to Iran.

Users are reporting via social media that Slack, the $7 billion work chat app, is shutting down their accounts because they live in Iran, which is under newly-reimposed sanctions. 

The problem, these users say, is that they don't live in Iran, but that they are ethnically Iranian or had recently traveled to the country. Some of these users include a PhD student living in Canada, and a software engineer, who is a U.S. citizen living in Pennsylvania. Amir Omidi, a software engineer at IPinfo, said that he found out his account got shut down Wednesday night.

Slack did not respond to a request for comment at the time of publication.

These users say they received a message from Slack saying that the company no longer allows use of its product in sanctioned countries and regions, including Cuba, Iran, North Korea, Syria and the Crimea region of Ukraine. The U.S. had recently reimposed all sanctions on Iran. These sanctions, which went into effect on November 5, include strict oil sanctions, as well as sanctions that cover the shipping and financial sectors.

The message said that Slack identified those users' accounts as being from one of those countries, so they shut down their account. The problem is, many of these users are neither living in Iran, nor do they have professional ties to Iran.

"No way to prove that I'm not living in Iran and not working with Iranians on slack. Nope. Just hello we're banning your account," Omidi tweeted.

Since then, he tweeted that he's had to track down his co-workers to let them know why his account disappeared. He also contacted Slack to look into his account getting shut down, he says. 

"For anyone considering creating an international team using Slack. Just don't. This predatory business practice is unbelievable," Omidi tweeted.

Likewise, Amir Abdi, a PhD student at the University of British Columbia, also said on Wednedsay that his account was shut down.'"Is Slack shutting down accounts of those ethnically associated with Iran?! And what's their source of info on my ethnicity?" Abdi tweeted.

Abdi also wrote that it may have been possible that this was because he had traveled to Iran before.  Another user tweeted that he had previously traveled to Iran and had his account closed, and Slack replied that its systems may have detected an account with an IP address originating from an embargoed country like Iran.

Likewise, users who actually do live in Iran tweeted that they did not receive any heads-up that their accounts would be shut down.

Read more: Slack cofounder Cal Henderson says having Microsoft become your top competitor is like when 'you slowly boil a frog'

Slack, last valued at over $7 billion in a funding round last year, is said to be planning an IPO in 2019.