TigerVNCViewer: unable to connect to socket: Connection Refused (10061)

When trying to connect from a Win10 client to a Ubuntu 18.04 server using TigerVNCViewer, I get an error indicating the connection was refused. This had been previously working, but apparently stopped working after a software update on the Ubuntu server.

There should not be any firewall active and vncserver and vncpasswd have been executed on the server. The output from several diagnostic commands is included below.

Any help in resolving this issue is greatly appreciated.

Commands on Win10 client:

TigerVNCViwer
unable to connect to socket: Connection refused (10061)

Commands on WSL on Win10 client:

• Note that default telnet and ssh connections successful to 192.168.1.10 from WSL and Cygwin on Win10 client

$ telnet 192.168.1.10 5901
Trying 192.168.1.10...
telnet: Unable to connect to remote host: Connection refused

Commands on Ubuntu server:

$ uname --all
Linux FooHost 5.3.0-28-generic #30~18.04.1-Ubuntu SMP Fri Jan 17 06:14:09 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
$ ifconfig
enp3s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.1.10 netmask 255.255.255.0 broadcast 192.168.1.255 inet6 fe80::eb13:faea:f55c:e235 prefixlen 64 scopeid 0x20<link> ether 10:bf:48:87:25:f6 txqueuelen 1000 (Ethernet) RX packets 11209 bytes 10099146 (10.0 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 6759 bytes 2418488 (2.4 MB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 6678 bytes 382526 (382.5 KB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 6678 bytes 382526 (382.5 KB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
$ vncserver --list
TigerVNC server sessions:
X DISPLAY # PROCESS ID
:1 3927
$ sudo iptables --list
Chain INPUT (policy ACCEPT)
target prot opt source destination
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
$ sudo ufw status
Status: inactive
$ sudo lsof -P -i
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
systemd-r 491 systemd-resolve 12u IPv4 1971 0t0 UDP localhost:53
systemd-r 491 systemd-resolve 13u IPv4 1972 0t0 TCP localhost:53 (LISTEN)
avahi-dae 847 avahi 12u IPv4 24646 0t0 UDP *:5353
avahi-dae 847 avahi 13u IPv6 24647 0t0 UDP *:5353
avahi-dae 847 avahi 14u IPv4 24648 0t0 UDP *:34033
avahi-dae 847 avahi 15u IPv6 24649 0t0 UDP *:44878
sshd 1079 root 3u IPv4 30370 0t0 TCP *:22 (LISTEN)
sshd 1079 root 4u IPv6 30372 0t0 TCP *:22 (LISTEN)
dhclient 1169 root 6u IPv4 28935 0t0 UDP *:68
cupsd 2762 root 6u IPv6 26605 0t0 TCP ip6-localhost:631 (LISTEN)
cupsd 2762 root 7u IPv4 26606 0t0 TCP localhost:631 (LISTEN)
cups-brow 2763 root 7u IPv4 33998 0t0 UDP *:631
sshd 2848 root 3u IPv4 33644 0t0 TCP Cheaptos:22->192.168.1.11:1629 (ESTABLISHED)
sshd 2954 rbohl 3u IPv4 33644 0t0 TCP Cheaptos:22->192.168.1.11:1629 (ESTABLISHED)
Xtigervnc 3927 rbohl 7u IPv4 34521 0t0 TCP localhost:5901 (LISTEN)
Xtigervnc 3927 rbohl 8u IPv6 34522 0t0 TCP ip6-localhost:5901 (LISTEN)
inetd 4397 root 7u IPv4 39902 0t0 TCP *:23 (LISTEN)

2 Answers

Try starting vncserver with the parameter -localhost no, this works for me.

vncserver -localhost no

You will need to install dbus-x11, then restart both Win-KeX and vnc-server.

1. Shut down VNC Server and Kex:

vncserver --kill :*
kex kill
kex stop

2. Install dbus-x11:

sudo apt update
sudo apt install dbus-x11

3. Restart Win-Kex:

kex -s

This YouTube video has more information that might be useful.