Hi Steve,
I did what you suggested me and I can access to my wp-admin page and to my site, but everything is super slow, therefore I checked the site speed with Google pagespeed insignt and a timeout message is returned. I had this issue already in the past and it was somehow due to something in my tables.
I just noted that some tables in phpmyadmin have a “overhead”. I have no clue why and how to fix it.
I will try to contact the support of the pluging I’m using.
Thanks,
Cristian
P.S.
I could not find the folder /var/log/messages. I found instead the folder /var/log/mysql in which I had error logs.