This article applies to all TeamViewer users who have not upgraded the TeamViewer software to the latest version and see the error message: "Unable to connect - Reason unknown".
TeamViewer recommends that all users download and start using the latest version of TeamViewer on all supported operating system platforms.
When you see a pop-up offering you to Update Now, please check the version of the TeamViewer software you are currently using, and immediately update to the latest version of TeamViewer.
Check TeamViewer version
- Windows: TeamViewer --> Help --> About TeamViewer --> Version
- macOS: TeamViewer --> About TeamViewer --> Version
- Linux: TeamViewer --> Help --> About TeamViewer --> Version
- Android: TeamViewer --> Settings --> Version
- iOS: TeamViewer --> Settings --> Advanced Settings --> Version Information
At the same time, please check the compatibility of operating systems and software versions: Supported operating systems.
When you see the error messages in TeamViewer with Reason Unknown, and the connection cannot be established, please download and update TeamViewer to the latest version.
Windows, Linux and macOS
When the TeamViewer software pops up with an error: Unable to connect - Reason unknown, please update TeamViewer to the latest available version.
Mobile devices - Android and iOS
When the TeamViewer remote control app shows the following error:
Android: Could not connect to partner
iOS: Unable to connect - A connection could not be established. Reason unknown
Please update the TeamViewer remote control app to the latest version via your app store.
- Android: Download the latest version of TeamViewer remote control
- iOS: Download the latest version of TeamViewer remote control