Could only find one reference using “the user might login in another computer” – Google Search, who also could not find out why this error happened:
When trying to log in on FortiClient, I get an error message that says, “the user might login in another computer” I assume that could mean that I’m logged in on another machine elsewhere? I could not find any information confirming that.
[WayBack] Error Message | Fortinet Technical Discussion Forums
So I reached out to Fortinet, the makers of Forticlient:
[WayBack] Jeroen Pluimers on Twitter: “@Fortinet what could cause this? Searching for the message “The user might login in another computer” did not get me any further: https://t.co/Bl4KoWJ7IB FortiClient 6.6.1.723 on MacOS High Sierra.…”
–jeroen