Fix on macOS AnyConnect error: cannot confirm it is connected to your secure gateway. The local network may not be trustworthy. Please try another network
Open terminal and do the following (you will need administrator rights on your Mac)
cd /opt/cisco/AnyConnect
sudo nano AnyConnectLocalPolicy.xml
Then edit the field for ExcludeMacNativeCertStore to "true"
<ExcludeMacNativeCertStore>true</ExcludeMacNativeCertStore>
Quit AnyConnect and start it up again.
You will now receive a certificate warning with the option to continue and, if available, install the certificate.