https://help.tallysolutions.com/docs/td9rel54/td9/getting_started_with_td9/licensing/configure_license.htm

Configuring Your Tally.Developer 9 License

The option Configure Existing License must be used in a LAN environment to configure an existing license to your Tally.Developer 9 from the Tally Gateway Server .

To configure the existing license

1. Right-click tally.developer.exe , and select Run as Administrator .

2. Go to License > Configure Existing License . The Configure Existing License screen appears as shown below:

3. Enter the Tally Gateway Server name and Port number .Alternatively, click Search Gateway Server(s) to list the compatible gateway servers.

4. Click Submit to configure the license.

Note: Go to License > License Info to view license, version, and subscription-related information.