Steps to reproduce:

1. Create the nxlog directory with full permissions and the nx user as owner
2. Enter a path to the folder in key CommonLogDirectory in node.cfg file
3. Restart nxserver using command: 

sudo service nxserver restart

As a result, connection to that host is no longer possible due to wrong permissions being assigned to the newly created server.log file:
-rw------- 1 nx      nx    nxserver.log

In some cases, the nxnode service is also disabled.

As a workaround, remove server.log and then restart nxserver:

sudo rm /var/tmp/nxlog/server.log
sudo /etc/NX/nxserver --restart

In that case permissions to server.log file are assigned correctly:
-rw-rw--w- 1 nx        root      server.log