White screen in web browser

I am getting the white screen after installing your software on Ubuntu 16.04.6. Accessing on port 8080 lets me download the portable desktop client. It fails to connect to the postgresql database. Please assist.

There are two log files that you could see in these paths:

/opt/metasfresh/log
/opt/metasfresh/metasfresh-webui-api/log

and two properties files that you can review in case they are not configured correctly:

/opt/metasfresh/metasfresh.properties
/opt/metasfresh/metasfresh-webui-api/metasfresh.properties

in these files you will find the connection configuration to the database in the line

Connection=xyzCConnection[name=xxxxxx-VirtualBox{dsanguano-VirtualBox-metasfresh-metasfresh},AppsHost=xxxxxx-VirtualBox,AppsPort=61616,AppsUserName=null,AppsPassword=null,type=PostgreSQL,DBhost=xxxxxx-VirtualBox,DBport=5432,DBname=metasfresh,UID=metasfresh,PWD=metasfresh]

DBhost:
IP of the machine that is the database if it is an installation in Ubuntu you can use localhost
DBport:
postgres default port is 5432
DBname:(database name)
used by default metasfresh
UID:(database user)
used by default metasfresh
PWD: (database password)
used by default metasfresh