You can query logs on the VPN tunnel management page and troubleshoot failures during the VPN tunnel connection according to the log information.
Log in to the VPC console.
Click VPN Connection > VPN Tunnel on the left sidebar to go to the management page.
On the VPN Tunnel management page, click More > Logs on the right of the tunnel to go to the log retrieval page.
You can view the log details in different time frames on the log retrieval page.