Cannot access to my home server via WireGuard

I am trying set up vpn to get access to my home server.
I created a domain on Duck DNS, configure a cron, make a port forwarding on router(51820), install pivpn on server with created public DNS, create a user and still have no access to my home server from different ISP.
Also ping port via nmap, and it’s open.
What am I doing wrong?