Thanks for reporting this.
Tunnelblick did have a problem getting update information from the Tunnelblick website (
https://tunnelblick.net), presumably when it checked for updates when it was launched. Otherwise it wouldn't have put up the warning.
But the warning should be removed if a later attempt to get update information succeeded, and that apparently isn't happening –
so that's bug in Tunnelblick.
You should be able to clear the warning triangle by quitting Tunnelblick and then restarting it. If the same warning appears again, then a problem getting the update information happened again. That could mean there is a problem – perhaps an intermittent problem – with your Internet connection, or with the Tunnelblick website.
This could also happen when you start your computer if network access isn't available when Tunnelblick launches but becomes available later. For example, if the Internet connection takes some time to become active, your computer is set up to log you in automatically when it is started, and Tunnelblick is launched when you log in. In that situation, it is possible that Tunnelblick would check for updates before the Internet is available. If that's the situation, then until the bug is fixed you'll have to quit and relaunch Tunnelblick to get rid of the warning triangle.