Ensure you are using the correct tunnel app for which the file was created.
If it is not a config file, it may be an old, obsolete image thumbnail format. Download Telenor File tnl
for this file? (e.g., getting free data, accessing a restricted site) What app are you trying to use to open it? Ensure you are using the correct tunnel app
If you are looking for free internet browsing, using official methods is recommended: Use the My Telenor App to manage settings. How to Use
Official Telenor settings are typically delivered via SMS or manual APN configuration, not through custom .tnl files. How to Use .tnl Files for Telenor (General Guide)
Select "Import" or "Restore" and browse for the downloaded .tnl file.
A "Telenor .tnl" file is often associated with configuration files used in third-party VPN tunnel applications (like Open Tunnel or TLS Tunnel) to access free or specific internet packages. These files are not official Telenor files, but rather community-created configurations used for networking tricks.