1. Run the following command in the terminal:

systemextensionsctl list | grep skyfirenetworks

If the command output contains

* QL5GS2Q47H com.skyfirenetworks.macvpn.networkextension (3.1.7/72) networkextension [activated waiting for user]

The “[activated waiting for user]” in the output means you need to allow SkyFire to run. As shown in the figure, open “Privacy and Security” and click “Allow” in “Security”. Enter the system password and run SkyFire.  

2. If the above method does not work, and there is no "Allow" button in "Security" of "Privacy and Security", please run the following command to remove the SkyFire extension:

systemextensionsctl uninstall QL5GS2Q47H com.skyfirenetworks.macvpn.networkextension

If the output of the command is

At this time, this tool cannot be used if System Integrity Protection is enabled.
This limitation will be removed in the near future.
Please remember to re-enable System Integrity Protection!

You need to turn off Apple's System Integrity Protection (SIP) before running the above command to remove the extension.

After removing the extension command, uninstall SkyFire, restart the computer, and install the SkyFire app again. When installing again, please be sure to strictly follow the installation tutorial we provide.