nmap puts service as "tcpwrapped" even though nignx is running on it

I have my own little website running with nginx on a digitalocean server.

I wanted to try to nmap it just for the practice, so I tried running

nmap -v -A -sV xx.xx.xxx.xxx

It scans and comes back with this response:

PORT    STATE  SERVICE    VERSION
22/tcp  open   tcpwrapped
|_ssh-hostkey: ERROR: Script execution failed (use -d to debug)
80/tcp  open   tcpwrapped
|_http-server-header: nginx/1.18.0 (Ubuntu)
| http-title: Welcome | MyWebApp
|_Requested resource was /public
443/tcp closed https

So the service on port 80 shows up as 'tcpwrapped' even though i know it's running nginx. the scan is however able the see in the serverheader that I am running nginx/1.18.0 (Ubuntu)-

What can be the reason that nmap can't tell which service I am running, when I am clearly running nginx?