vpn keeps turning off and on

Hello Marc, 
Thank you for contacting AVG Community Support.
We understand that your VPN keeps turning off and on.
We are really sorry to know this. We'll certainly check and help you out.
Could you please let us know when you started facing this issue? 
If AVG Secure VPN is unable to establish a connection, try the following troubleshooting steps:
Check that your internet connection works when AVG Secure VPN is disconnected. If your internet connection isn't working, check your network configuration.
Select a different AVG server location.
Disconnect other VPN services that may be running on your Mac. If you are connected to another VPN, it is likely that AVG Secure VPN won't work properly.
Restart your Mac and try connecting to AVG Secure VPN again.
Some routers have the option to enable or disable IPsec, sometimes displayed as VPN passthrough. For AVG Secure VPN to connect and function properly, ensure that IPsec or VPN passthrough is enabled.
Check the configuration of your firewall. Consult your firewall vendor to check that UDP port 500 and UDP port 4500 are open on your firewall.
Confirm that your subscription is active. Open AVG Secure VPN, and go to ☰ Menu ▸ Subscription. Check your subscription details under Subscription Information.
If AVG Secure VPN is still unable to establish a connection, try to uninstall and reinstall the application. For detailed instructions, refer to the following articles:
Uninstalling AVG Secure VPN (https://support.avg.com/SupportArticleView?l=en&urlName=Uninstall-AVG-Secure-VPN)
Installing AVG Secure VPN (https://support.avg.com/SupportArticleView?l=en&urlName=Install-AVG-Secure-VPN)
Please do try the above steps and let us know if you still face the same issue. 
Thank you and keep us updated.