One of the solution is using the PRTG like the following:
https://www.paessler.com/howto-free-network-monitoring
Thursday, June 22, 2023
How to monitor a Internet line performance to specific website
Failed to connect to OpenVPN server after upgrade ASUS router firmware
On the OpenVPN client, you receive the following error:
AUTH_FAILED (Authentication Fail)
Solution:
Change the "Allow only specified clients" to "No"
