Hello Sirs,
after your suggestions, I downloaded and reinstalled both the MT5 and ZorroS platforms;
I launched only one Zorro's instance with Z12 and everything worked fine for about a month;
the trades have been entered succesfully;
total or partial closings have been carried out correctly.
Unfortunately I was forced to upgrade (win10 home edition cannot allow to disable the updates, or probably yes tampering some dwords in the filesystem);
before the win_update, I stopped and restarted trading (without closing open positions) for 5 or 6 times, finding that "all" the transactions were resumed correctly;
some seconds later, after stopping trading (without closing open positions), I stopped Zorro to restart it immediately: Only phantom trades were resumed, but not the real ones.
I have now only installed one instance of Zorro + MT5 on AWS EC2, so that I can set it to avoid win_updates.
I am thinking that when the next official version of Zorro will be released, I will be forced to stop and restart Zorro;
I would not like to face the same problems of "not resumed" real trades, to be closed manually.