Error 500 in transfer of OJS to another hosting "SQLSTATE[HY000] [1130] Host '127.0.0.1' is not allowed to connect to this MySQL server"

Hello!
@marc You are very kind to all this help. Sorry for the delay in replying, I was busy at work and I could not dedicate myself to the site.
When I said I didn’t have access to FTP it was because I was in the office, and didn’t have access to a PC.
I don’t have a webmaster, I’m trying to learn how to manage this site myself. The hosting support said that the error I reported to in this forume means that I should change all occurrences of 127.0.0.1 to “localhost”.
@henriqueramos My DB host is “localhost: 3306”

  • I cleared the browser cache.
  • I don’t understand how to clear the server caches, since it is not possible to log into the OJS site backed in any way.
  • The credentials of the DB I have chosen by myself.
  • The administrator of the yes is me.
  • I cannot raise the PHP version to 7.2 because otherwise the errors increase and become like the ones I brought at the beginning of this thread. Instead using at most, version 7.0.33 remains a single one-line error, which I report for the second time here:

Parse error: syntax error, unexpected '?', Expecting variable (T_VARIABLE) in /var/www/vhosts/my-website.com/mys-subdomain.my-website.com/lib/pkp/classes/notification/PKPNotificationOperationManager. inc.php on line 374

I will post the config.inc.php file in a few hours, because now I have technical problems.
Thanks so much!