My site suddenly went down with 500 errors on all pages and no recent changes:

Here's the error log... (XXX to cover private info)

[20-Feb-2024 07:49:22 UTC] PHP Fatal error:  Uncaught Error: Call to undefined function IPS\mb_internal_encoding() in /home/XXX/public_html/forums/init.php:565
Stack trace:
#0 /home/XXX/public_html/forums/init.php(1598): IPS\IPS::init()
#1 /home/XXX/public_html/forums/index.php(12): require_once('/home/XXX/pub...')
#2 {main}
  thrown in /home/XXX/public_html/forums/init.php on line 565
[20-Feb-2024 07:49:22 UTC] PHP Fatal error:  Uncaught Error: Call to undefined function IPS\mb_internal_encoding() in /home/XXX/public_html/forums/init.php:565
Stack trace:
#0 /home/XXX/public_html/forums/init.php(1598): IPS\IPS::init()
#1 /home/XXX/public_html/forums/index.php(12): require_once('/home/XXX/pub...')
#2 {main}
  thrown in /home/XXX/public_html/forums/init.php on line 565

Any ideas?

Your PHP is missing mbstring extension. If you or your hosting provider upgraded PHP, it is missing extensions required for the software to function. Please also make sure you're running PHP 8.0 or PHP 8.1.

Can using the following requirements checker script:

 

 

Your PHP is missing mbstring extension. If you or your hosting provider upgraded PHP, it is missing extensions required for the software to function. Please also make sure you're running PHP 8.0 or PHP 8.1.

Can using the following requirements checker script:

 

Thanks, I will follow up with my host,