My parents are using VPN, but it's difficult to connect. Can I connect to online classes?

The SRAS VPN service is required for course registration and access to the AMI,

You don't need to be connected to a VPN to teach online.

Is your home line wired (FLET'S, au Hikari, Nuro Hikari, etc.)?
If it is wired, Line speed can be measured at 
https://fast.com .
(Please note that wireless will consume packet data.）

In real-time delivery lessons such as Zoom,
Normally, if you get about 1.2 Mbps, you can watch with sufficient image quality.