Build that timeout on the deploy step


I am trying to automate the generation of a bunch of doxygen documentations (multiple versions of a software).
All is working well but I have a problem at the end of my build on the deploy step when deploying to GitHub page my build docs with the following output.

Deploying application
Initialized empty Git repository in /tmp/d20190828-7992-16ljbem/work/.git/
Repo created successfully
Switched to a new branch 'gh-pages'
An orphan branch gh-pages created successfully
cd -
cd /tmp/d20190828-7992-16ljbem/work
Copying /home/travis/build/jtraulle/dolibarr-doxygen/build contents to /tmp/d20190828-7992-16ljbem/work (workdir: /tmp/d20190828-7992-16ljbem/work)...

No output has been received in the last 10m0s, this potentially indicates a stalled build or something wrong with the build itself.
Check the details on how to adjust your build configuration on:

The build has been terminated

The directory to publish in huge so, it is not a surprise that it take more than 10 minutes.

I have tried to add verbose: true to my deploy step but it does not change anything.

Is there any way to get this to work ?

Here is my .travis.yml file :

The failing job :

And the build matrix :