Please check if any of your disk partitions is full. Pay special attention to the OBS log directory:
Windows – C:\Program Files\Offsite
Backup Server\logs
Linux – /usr/local/obs/logs
Mac OS X – /Applications/OBS/logs

It is safe to delete any log files here from the system.

Also, are you using non-default TCP port for the backup server? If so, please append the port number of your HTTP (NOT HTTPS) connector to the [Manage System] -> [Host Name] entry, e.g. backup.yourcompany.com:8080

If you are not using custom port, open a browser on the backup server and type in the value of [Manage System] -> [Host Name] as an URL. Check if you get the backup server homepage. If you cannot get the webpage, try altering the URL until you can reach the server. You can then put this value in the [Manage System] -> [Host Name] field. (Please omit the page name, i.e. /index.jsp, from this entry)

If you are on Linux, please try setting the LD_ASSUME_KERNEL environment variable in $OBS_HOME/bin/startup.sh by adding the following line and restart the OBS service:

export
LD_ASSUME_KERNEL=2.4.19

If you are running OBS on Linux Kernel 2.6, you could have run into the compatibility problem of running Java program on Linux Kernel 2.6 (More info on: http://www.jroller.com/page/dissonance/20050630#fedora_core_4_and_jdk)

Please try this to fix this problem:

Open $OBS_HOME/bin/startup.sh

Add “-Djava.net.preferIPv4Stack=true” to the command line argument. i.e. change the line:
export CATALINA_OPTS="-Xms64m -Xmx512m -client
-Dsun.net.inetaddr.ttl=10800 -Dnetworkaddress.cache.ttl=10800
-Dsun.net.inetaddr.negative.ttl=0 -Dnetworkaddress.cache.negative.ttl=0"

to

export CATALINA_OPTS="-Xms64m -Xmx512m -client
-Dsun.net.inetaddr.ttl=10800 -Dnetworkaddress.cache.ttl=10800
-Dsun.net.inetaddr.negative.ttl=0 -Dnetworkaddress.cache.negative.ttl=0
-Djava.net.preferIPv4Stack=tru

Restart the backup service by running [$OBS_HOME/bin/shutdown.sh] and then [$OBS_HOME/bin/startup.sh]