Thank you for all the information you provided. We tried to reproduce the issue but everything worked after installing the latest version of the stack and rebooting the server.
I only needed to start the services after rebooting:
ubuntu@ip-172-31-33-204:~$ sudo /opt/artifactory-5.6.3-0/ctlscript.sh start
Using CATALINA_BASE: /opt/artifactory-5.6.3-0/apache-tomcat
Using CATALINA_HOME: /opt/artifactory-5.6.3-0/apache-tomcat
Using CATALINA_TMPDIR: /opt/artifactory-5.6.3-0/apache-tomcat/temp
Using JRE_HOME: /opt/artifactory-5.6.3-0/java
Using CLASSPATH: /opt/artifactory-5.6.3-0/apache-tomcat/bin/bootstrap.jar:/opt/artifactory-5.6.3-0/apache-tomcat/bin/tomcat-juli.jar
Using CATALINA_PID: /opt/artifactory-5.6.3-0/apache-tomcat/temp/catalina.pid
/opt/artifactory-5.6.3-0/apache-tomcat/scripts/ctl.sh : tomcat started
/opt/artifactory-5.6.3-0/apache2/scripts/ctl.sh : httpd started at port 80
I also stopped and started the machine that caused a IP change and everything worked as expected too.
Can you confirm that all the services are up and running when accessing the instance?
sudo /opt/artifactory/ctlscript.sh status
Regarding the application itself, did you perform any change before rebooting the instance? We checked the logs of the application and we saw this error in the Tomcat's logs
Caused by: java.util.concurrent.ExecutionException: ma.glasnost.orika.MappingException: exception while creating object factory for org.jfrog.access.server.model.PermissionImpl
It seems that there is an issue when upgrading the application but this is not your case.