Hello there

A user is reporting an issue that's been hard to pin down the root cause.
His desktop is a macosx 10.11.5, from which he connects to a centos 6.5 server where he runs xmgrace 5.1.22 to check his simulation outputs.
After a (seemingly random) while, he is no longer able to run xmgrace, needing to logout and login back to run xmgrace again.
The message is (to me) quite cryptic:

"Can't open display
Failed initializing GUI, exiting"

I am not able to reproduce the error from two different Linux distros (none of them centos), even after several hours connected.


Libraries used by xmgrace:
=======================================
cyrus-sasl-lib-2.1.23-13.el6_3.1.x86_64
expat-2.0.1-11.el6_2.x86_64
fftw2-2.1.5-21.el6.x86_64
fontconfig-2.8.0-3.el6.x86_64
freetype-2.3.11-14.el6_3.1.x86_64
glibc-2.12-1.132.el6.x86_64
hdf5-1.8.5.patch1-9.el6.x86_64
keyutils-libs-1.4-4.el6.x86_64
krb5-libs-1.10.3-10.el6_4.6.x86_64
libcom_err-1.41.12-18.el6.x86_64
libcurl-7.19.7-37.el6_4.x86_64
libICE-1.0.6-1.el6.x86_64
libidn-1.18-2.el6.x86_64
libjpeg-turbo-1.2.1-3.el6_5.x86_64
libpng-1.2.49-1.el6_2.x86_64
libselinux-2.0.94-5.3.el6_4.1.x86_64
libSM-1.2.1-2.el6.x86_64
libssh2-1.4.2-1.el6.x86_64
libuuid-2.17.2-12.14.el6.x86_64
libX11-1.5.0-4.el6.x86_64
libXau-1.0.6-4.el6.x86_64
libxcb-1.8.1-1.el6.x86_64
libXext-1.3.1-2.el6.x86_64
libXft-2.3.1-2.el6.x86_64
libXmu-1.1.1-2.el6.x86_64
libXp-1.0.0-15.1.el6.x86_64
libXpm-3.5.10-2.el6.x86_64
libXrender-0.9.7-2.el6.x86_64
libXt-1.1.3-1.el6.x86_64
netcdf-4.1.1-3.el6.5.x86_64
nspr-4.10.2-1.el6_5.x86_64
nss-3.15.3-6.el6_5.x86_64
nss-softokn-freebl-3.14.3-9.el6.x86_64
nss-util-3.15.3-1.el6_5.x86_64
openldap-2.4.23-34.el6_5.1.x86_64
openmotif-2.3.3-6.1.el6_4.x86_64
openssl-1.0.1e-16.el6_5.4.x86_64
t1lib-5.1.2-6.el6_2.1.x86_64
xbae-4.60.4-12.el6.x86_64
zlib-1.2.3-29.el6.x86_64
=======================================


xorg server version is below:
=======================================
xorg-x11-proto-7.6-25.el6.noarch
xorg-x11-server-common-1.13.0-23.1.el6.centos.x86_64
xorg-x11-server-utils-7.5-13.el6.x86_64
xorg-x11-server-Xephyr-1.13.0-23.1.el6.centos.x86_64
xorg-x11-server-Xorg-1.13.0-23.1.el6.centos.x86_64
=======================================


The user also did tried some ssh options like:
=======================================
TCPKeepAlive yes
ServerAliveInterval 300
ServerAliveCountMax 99999
Compression yes
CompressionLevel 6
=======================================


Upgrading to the latest xquartz release also did not fixed the issue.
What else can be done to zero in on the cause of the error?


TIA,
Fabricio