Old MySQL code will not work with php7. Your best solution will be to downgrade php versions to v6 or below.
You could also update your pages to mySQLi with Data Bridge v2 or re-create them with MySQLi Server Behaviors. That would be a rather large project if you have lots of sites with lots of pages that need to be addressed, so I'd probably look into finding a server that supports mysql in the meantime even if you go down that route.