How to remote access my cloud dashboard via VPN (PPTP)

I know that this question has been asked by many people. But I also want to know how to solve it.
I tried port mapping,but it‘s failed. Page displayed 403 forbidden.
I set up a VPN server on the router. I tried PPTP and OpenVPN, page also displayed 403 forbidden.
I am sure my VPN is worked, I can remotely access my router via an intranet address.
I want to know why this is, and how to remote access my cloud dashboard via VPN.
Thanks !

Just because you can access the router does not mean VPN is working. Typically you need to be able to access other devices/computers through the VPN tunnel for VPN to work properly.

If you cannot access the the my cloud or other local network devices then you have a configuration problem with your VPN Server or client. I would start by ensuring all devices are using the same IP subnet range and that the VPN Server isn’t isolating the VPN Clients from the main local network. See the setup docs for the VPN Server for setup information.

Can you access files on your drive via the VPN?

Devices that VPN into my router appear with a different subnet than the balance of my network.

I won’t be able to prowl my devices until tomorrow. . .but I think there is a setting that will disable access from remote networks to you NAS. (If you are on a different subnet. . . this setting will block access). I have not done this in a while, but IIRC, I could access files, but I was able to block access to the dashboard.