Sorry, it seems that after the first installation, I have to kill X and relogin , then incync is ready to use.
After restarting X, insync start --no-daemon will make insync work properly. Then i ran insync start, and it starts normally.
It’s really strange.
I am having the same issue now. Worked fine until I did a zypper dup (Update OS)
insync start --no-daemon gives the same error as JZ_H. insync start --no-daemon --headless works OK.
Here is what I think is the relevant strace entries:
connect(7, {sa_family=AF_UNIX, sun_path=@"/tmp/.X11-unix/X0"}, 20) = 0
getpeername(7, {sa_family=AF_UNIX, sun_path=@"/tmp/.X11-unix/X0"}, [124->20]) = 0
uname({sysname=“Linux”, nodename=“motop.codejunkie.net”, …}) = 0
access("/tmp/xauth-1001-_0", R_OK) = 0
openat(AT_FDCWD, “/tmp/xauth-1001-_0”, O_RDONLY) = 8
fstat(8, {st_mode=S_IFREG|0600, st_size=50, …}) = 0
read(8, “\1\0\0\5motop\0\0010\0\22MIT-MAGIC-COOKIE-1”…, 4096) = 50
read(8, “”, 4096) = 0
close(8) = 0
fcntl(7, F_GETFL) = 0x2 (flags O_RDWR)
fcntl(7, F_SETFL, O_RDWR|O_NONBLOCK) = 0
fcntl(7, F_SETFD, FD_CLOEXEC) = 0
poll([{fd=7, events=POLLIN|POLLOUT}], 1, -1) = 1 ([{fd=7, revents=POLLOUT}])
writev(7, [{iov_base=“l\0\v\0\0\0\0\0\0\0\0\0”, iov_len=12}, {iov_base="", iov_len=0}], 2) = 12
recvfrom(7, 0x55b31c23e800, 8, 0, NULL, NULL) = -1 EAGAIN (Resource temporarily unavailable)
poll([{fd=7, events=POLLIN}], 1, -1) = 1 ([{fd=7, revents=POLLIN|POLLHUP}])
recvfrom(7, “\0\26\v\0\0\0\6\0”, 8, 0, NULL, NULL) = 8
recvfrom(7, “No protocol specified\n\0\0”, 24, 0, NULL, NULL) = 24
write(2, “No protocol specified\n”, 22No protocol specified
) = 22
shutdown(7, SHUT_RDWR) = 0
close(7) = 0
write(2, “insync.py: cannot connect to X s”…, 41insync.py: cannot connect to X server :0
) = 41
write(6, “@”, 1) = 1
close(6) = 0
close(5) = 0
rt_sigaction(SIGCHLD, NULL, {sa_handler=0x7f60090ec950, sa_mask=[], sa_flags=SA_RESTORER|SA_SIGINFO|SA_NOCLDSTOP, sa_restorer=0x7f600fb27270}, 8) = 0
rt_sigaction(SIGCHLD, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=SA_RESTORER, sa_restorer=0x7f600fb27270}, NULL, 8) = 0
exit_group(1) = ?
+++ exited with 1 +++
sgonzalez@motop:~> ls -l /tmp/.X11-unix/X0
srwxrwxrwx 1 root root 0 Feb 6 16:20 /tmp/.X11-unix/X0
I was able to get it working again non-headless by logging out of KDE and running rm -rfv - - ~/.Xauthority /tmp/.X11-unix /tmp/xauth-*
I have the same problem, some time it works and some times dind’t work
Is there any update on this? Having to delete all the auth files is cumbersome and running headless really reduces functionality. If further details are needed I am happy to provide.
@sgonzalez Are you still experiencing the same issue on Insync 1.4.5? We’ll take another look at this issue. We’re sorry for the inconvenience.
Yes, it is still occuring with latest insync.
sgonzalez@motop:~> insync --version
1.4.5.37069
sgonzalez@motop:~> insync start --no-daemon
No protocol specified
insync.py: cannot connect to X server :0I did so last week, any update?
Hello, any update on this issue?
Hi Sal,
Our engineers are currently working on this issue. We’ll make sure to keep you posted once we are able to resolve this. 
I deeply apologise for the trouble.
I had a hdd failure last weekend and had to re-install opensuse tumbleweed. inSync has been working fine evey day since then, I assume opensuse addressed this bug themselves or the re-install fixed it.
Glad to know everything is good on your end! If you need any help, just shoot us a message anytime at support@insynchq.com.
I had a similar problem recently with Opensuse Leap 15.0 and Insync on one of my two machines. Got the same error “No protocol specified. insync.py: cannot connect to X server :0”.
With a little debuggin I found that the problem was that on my machine Xauthority files had the machine hostname without any domain, whereas uname reports the hostname with domain. The same difference seems to be in the strace provided in an earlier reply.
In my case I managed to solve the problem simply by adjusting my network settings.
I am having the same problem.
tthigpen@TonyLapTop:~> insync start --no-daemon
QIconvCodec::convertFromUnicode: using Latin-1 for conversion, iconv_open failed
QIconvCodec::convertToUnicode: using Latin-1 for conversion, iconv_open failed
No protocol specified
insync.py: cannot connect to X server :0
tthigpen@TonyLapTop:~> insync --version
1.4.9.37127
I have tried what other’s did but it still fails.
UPDATE: Re-ran the “rm -rfv - - ~/.Xauthority /tmp/.X11-unix /tmp/xauth-*” command as su and then logged off and on. Now insync is working.
Same here. I have had to run the same commands in order to get Insync working again on openSUSE Tumbleweed.
I am having to run the command every time I reboot.
Doesn’t work in my case (I’m on KDE5), and I don’t see any new advance in try to solving it. It’s very frustrating 
