Why I obtain this error message trying to deploy a project on TomCat (from NetBeans)? (The context failed to start)

I am not so into Maven and NetBeans (I used Eclipse and Ant in the past) and I have the following problem.

I have obtaine a project using the Maven feature named Project from Archetype and choosing the archetype specified from the tutorial (an archetype named entando-archetype-portal-bootstrap, that is an archetype that generate an Entando portal).

In the next NetBeans window I specified the project name as myfirstportal and as Group id I specified com.entando

I have no changed the default project path that is:

/home/andrea/NetBeansProjects/myfirstportal

Then, in the NetBeans projects tab I select my project and I perform the Maven Clean and build task that works for some seconds and that correctly end with a BUILD SUCCESS message.

So it seems that the build process is ok.

Then I select my project and I perform Run, so I choose my TomCat installation.

The starting process start but at the end I always obtain this error message:

ebapp assembled in [9582 msecs]
Building war: /home/andrea/NetBeansProjects/myfirstportal/target/myfirstportal.war

--- tomcat7-maven-plugin:2.1:exec-war-only (war-build-standalone) @ myfirstportal ---
------------------------------------------------------------------------
BUILD SUCCESS
------------------------------------------------------------------------
Total time: 31.067s
Finished at: Thu Jul 02 18:23:41 CEST 2015
Final Memory: 48M/233M
------------------------------------------------------------------------
NetBeans: Deploying on Apache Tomcat or TomEE
    profile mode: false
    debug mode: false
    force redeploy: true
Checking data source definitions for missing JDBC drivers...
Undeploying ...
undeploy?path=/myfirstportal
OK - Undeployed application at context path /myfirstportal
In-place deployment at /home/andrea/NetBeansProjects/myfirstportal/target/myfirstportal
Deployment is in progress...
deploy?config=file%3A%2Ftmp%2Fcontext5305066681099450691.xml&path=/myfirstportal
FAIL - Deployed application at context path /myfirstportal but context failed to start

As you can see at the end the process fail with this specific error message:

FAIL - Deployed application at context path /myfirstportal but context failed to start

What am I missing? What can I do to try to solve this issue?

Tnx