The issue you're facing likely stems from the licensing applied to your Layer 3 switch. Certain models, especially those with a base LAN or Layer 2 license, do not support advanced Layer 3 features like configuring a port as a routed port using the no switchport command. When the system rejects this command, it’s a clear indication that the current license doesn’t permit such functionality.
To address this, you’ll need to upgrade the license to one that supports Layer 3 features, such as the IP Base or IP Services license, depending on your switch model. You can confirm your current license type by using the show license command in privileged mode. Once you obtain the appropriate license from Cisco or your vendor, activate it through the license activation process and reboot the switch. After the upgrade, the no switchport command should work as expected, allowing you to configure the port as a routed port.
