I recognize that you just installed Big Sur on your computer and that you're having trouble with your VPN connection. Even though it appears that you have made efforts to enable the required apps in the Privacy/Security settings, you are still unable to connect to your VPN and are getting the warning "connection was terminated unexpectedly" when you try.
Given that you indicated using FortiClient 7.0.1.0060, there may be problems when utilizing this version with the Big Sur upgrade. One recommendation is to see whether a more recent FortiClient version is accessible and especially supports macOS Big Sur. It's critical to maintain your VPN client's compatibility with the most recent operating system.
You can attempt the following troubleshooting techniques in the interim:
1. Restart your computer: Restarting your computer will sometimes cure minor difficulties, including VPN connectivity issues.
2. Verify your VPN configurations a second time to make sure you have entered all the necessary information, including the server address, login information, and any other parameters that your VPN provider may have supplied.
3. Disable firewalls, antivirus programs, and other security programs that can interfere with your VPN connection temporarily. This can assist identify whether any conflicts are the root of the problem.
Since new versions frequently feature bug fixes and compatibility enhancements, keep in mind to keep your system and VPN client up to date.
I hope this helps you address your problem.
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