Nvr no remote access

[#1]

I have poe cctv with 8 cameras which was online and access to app mobile on old Virgin router, network cable attached to router, now new plusnet router in issues
I can search nvr via network find it, enter user, password says failed to connect.
Tried scan code, or manual, this is using wifi or mobile on Vodafone,
Took off firewall, and 5g network to usex2.4 ghz only
I have a wifi cctv camera that connected ok and ok on mobile app..

[#2]

Moderator's note:
Thread moved from Broadband to My Router

[#3]

Add necessary port forwards to your router or more securely add Tailscale/Wireguard on a Raspberry Pi or compatible router.