Critical Error

We received an email saying there has been a critical error on the site and I’m unable to access Shield Security from within the dashboard any longer. Here’s the error message:

WordPress version 6.6
Active theme: PEI Manufacturing (version 1.0) Current plugin: Shield Security (version 20.0.4) PHP version 7.4.33
Website: https://peimfg.com/

Error Details
=============
An error of type E_ERROR was caused in line 481 of the file /home/customer/www/peimfg.com/public_html/wp-content/plugins/wp-simple-firewall/src/lib/vendor/twig/twig/src/ExpressionParser.php. Error message: Uncaught Error: Class ‘Twig\Node\Expression\ArrayExpression’ not found in /home/customer/www/peimfg.com/public_html/wp-content/plugins/wp-simple-firewall/src/lib/vendor/twig/twig/src/ExpressionParser.php:481
Stack trace:
#0 /home/customer/www/peimfg.com/public_html/wp-content/plugins/wp-simple-firewall/src/lib/vendor/twig/twig/src/ExpressionParser.php(414): Twig\ExpressionParser->parseSubscriptExpression(Object(Twig\Node\Expression\NameExpression))
#1 /home/customer/www/peimfg.com/public_html/wp-content/plugins/wp-simple-firewall/src/lib/vendor/twig/twig/src/ExpressionParser.php(299): Twig\ExpressionParser->parsePostfixExpression(Object(Twig\Node\Expression\NameExpression))
#2 /home/customer/www/peimfg.com/public_html/wp-content/plugins/wp-simple-firewall/src/lib/vendor/twig/twig/src/ExpressionParser.php(183): Twig\ExpressionParser->parsePrimaryExpression()
#3 /home/customer/www/peimfg.com/public_html/wp-content/plugins/wp-simple-firewall/src/lib/vendor/twig/twig/src/ExpressionParser.php(78): Twig\ExpressionP