Problem: when you are trying to access Gravity forms, you encounter the following errors:

Uncaught TypeError: gform.applyFilters is not a function
Uncaught TypeError: gform.addAction is not a function
Uncaught TypeError: gform.initializeOnLoaded is not a function
Uncaught TypeError: gform.initializeOnLoaded is not a function

Solution: this happens because php dom is not enabled. Log in as root in ssh, run php -v to get your php version and based on this, run following commands (in this example, I make the assumption that php version is 8.1.

sudo apt install php8.1-dom
sudo systemctl restart apache2