The OneClick server does not react on requests and Out Of Memory messages are seen in the tomcat log.
The following message in the $SPECROOT/tomcat/logs/catalina.out (Linux) and $SPECROOT/tomcat/logs/stdout.log (Windows) file:
"java.lang.OutOfMemoryError: Java heap space"
The environment variable "_Java_Options" was set to the value "-XMS512". With this setting the maximum Java memory was overwritten. It was not enough and therefore created the error. This setting was completely removed and a correspondent setting was inserted in the OneClickService.conf under <$SPECTRUMROOT>/tomcat/bin edit: jvm_opt=-Xmx1280M
Because Java will have issues with a too high value, it was only increased to 1280M.