Homepage downloading cache (not showing the page

Hi All,

I installed W3 Total Cache 2 weeks ago. Two days ago my home page stopped working and instead forced a file download called “download” with no file extension. This was only for non logged in users. Logged in users did not have an issue and logged out users could see pages other pages aside from the home page.

I rebooted the server and it seemed to work again. Yesterday it happened again and I checked the logs:

[Thu Jul 13 00:27:36.686782 2023] [php:error] [pid 21121] [client 154.209.125.78:23612] PHP Fatal error:  Uncaught Error: Call to undefined function mysql_connect() in /var/www/html/wp-includes/class-wpdb.php:2054\nStack trace:\n#0 /var/www/html/wp-content/plugins/w3-total-cache/DbCache_WpdbNew.php(100): wpdb->db_connect()\n#1 /var/www/html/wp-includes/class-wpdb.php(773): W3TC\\DbCache_WpdbNew->db_connect()\n#2 /var/www/html/wp-content/plugins/w3-total-cache/DbCache_WpdbNew.php(221): wpdb->__construct()\n#3 /var/www/html/wp-content/plugins/w3-total-cache/DbCache_WpdbInjection.php(38): W3TC\\DbCache_WpdbNew->default_initialize()\n#4 /var/www/html/wp-content/plugins/w3-total-cache/DbCache_WpdbNew.php(107): W3TC\\DbCache_WpdbInjection->initialize()\n#5 /var/www/html/wp-content/plugins/w3-total-cache/DbCache_WpdbNew.php(362): W3TC\\DbCache_WpdbNew->initialize()\n#6 /var/www/html/wp-content/plugins/w3-total-cache/DbCache_WpdbInjection_QueryCaching.php(294): W3TC\\_CallUnderlying->initialize()\n#7 /var/www/html/wp-content/plugins/w3-total-cache/DbCache_WpdbNew.php(107): W3TC\\DbCache_WpdbInjection_QueryCaching->initialize()\n#8 /var/www/html/wp-content/plugins/w3-total-cache/DbCache_Wpdb.php(53): W3TC\\DbCache_WpdbNew->initialize()\n#9 /var/www/html/wp-content/db.php(81): W3TC\\DbCache_Wpdb::instance()\n#10 /var/www/html/wp-includes/load.php(570): require_once('...')\n#11 /var/www/html/wp-settings.php(124): require_wp_db()\n#12 /var/www/html/wp-config.php(128): require_once('...')\n#13 /var/www/html/wp-load.php(50): require_once('...')\n#14 /var/www/html/wp-blog-header.php(13): require_once('...')\n#15 /var/www/html/index.php(17): require('...')\n#16 {main}\n  thrown in /var/www/html/wp-includes/class-wpdb.php on line 2054

Any help would be much appreciated as W3 Total Cache is a notable improvement (apart from when it borks my site!)