tempstorage (which defines temporarystorage) does not work reliably under Zope 4+ (and therefore Plone 5.2.x); newer Zope versions therefore no longer include it.
I assume that your problem has the following cause: tempstorage is no longer available/activated (which makes temporarystorage unknown) and your zope.conf still uses it.
You could try to rerun buildout and check whether a newly generated zope.conf still uses temporarystorage. If this is not the case, this problem should be gone.
Otherwise, check the plone.recipe.zope2instance documentation (--> PyPI) and look for options to control the generation of the section temporary; this is related to sessions and therefore session might be part of the option name..
@dieter I rerun buildout and despite 2 compiling errors (Error while compiling language file), I was able to launch again Plone.
The command I launched:
sudo -u plone_buildout ./bin/buildout -Nv
I cannot edit the subject to add Solved, could an admin do it for me? Thanks by advance
@tkimnguyen unfortunately not, I closed the terminal.