Host name access not working

Ubuntu Server 20.04.3 LTS Linux 5.4.0-88-generic Hostname : plexserv

All was working fine, Plex and Samba set up, could access files on the server from Windows and MacOS machine no problem.

Then I ran a sudo apt update/upgrade, and things stopped working.

Had to dig the server out of the cupboard, connect a display and mouse to even get logged in.

Things are better now, PMS OK but I have the followingf issues

In Terminal on MacOS, I cannot access the server by it's hostname (plexserv). I had to type in the UIP address e.g. ssh user:192.168.X.X (whereas before I could type in ssh user:plexserv

Also in MacOS, my saved network location is not accessible. When clicked it just says cannot find 'plexserv'.

When I set this box up years ago, I think I had to do something to get the hostname accessible on other machines...

How can I fix this?

hosts file is below...

127.0.0.1 localhost
127.0.1.1 plexserv

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

Thanks.

This was a local issue on the MacOS device. I was using ProtonVPN via Wireguard, and when this is on, MacOS canont resolve the hostname. With VPN turned off, it can.