Tunnelblick stores usernames and passwords in the macOS keychain. If you have recently updated your password and are having authentication failures then you should first delete the keychain entries:

  1. Open keychain access utility by navigating to your Applications folder and then Utilities.
  2. Select Login under keychains and all elements under Category.
  3. In the search box in the top right, enter tunnelblick to filter all the tunnelblick keychain entries.
  4. Select all the tunnelblick entries, select edit | delete.
  5. Close tunnelblick and open it again and try to connect.

If you continue to have authentication issues please seeĀ My VPN password doesn't work (authentication failure). What can I do?