Random "Fatal error" using views

Hi,
I am using the latest version of DataBridge and I am getting "Fatal error" on pages where I created mySqli recordset on views.
The errors I am getting are:

"Fatal error: Uncaught Error: Call to a member function fetch_fields() on bool in /var/www/vhosts/ewineshop.it/httpdocs/webassist/mysqli/rsobj.php:211 Stack trace: #0 /var/www/vhosts/ewineshop.it/httpdocs/index.php(60): WA_MySQLi_RS->execute() #1 {main} thrown in /var/www/vhosts/ewineshop.it/httpdocs/webassist/mysqli/rsobj.php on line 211"

"Fatal error: Uncaught Error: Call to a member function fetch_assoc() on bool in /var/www/vhosts/in-people.it/httpdocs/zoom/meeting_add.php:81 Stack trace: #0 {main} thrown in /var/www/vhosts/in-people.it/httpdocs/zoom/meeting_add.php on line 81"

No errors if I use tables instead of views, but some of them are very complicated and I really need to use views.
If I restart mysql service on my plesk server, then problem is temporally fixed.

Any advice on how to solve this problem?

Thanks, Guido.