Sorry for the delayed answer, but I messed the server really bad and I had to reinstall the OS on it and I reinstalled Ubuntu on it, but the problem persists.
I've checked the PHP version and it is 7.0. Yet I turned on WP DEBUG and it shows a plenty of errors on the homepage! You can check the new installation at:
104.155.101.60 moldovacrestina.md
I beg your pardon once again and I've to thank you for your help! Hope we can figure out how to fix it!