Debugging the issue
There is a file at /var/log/apache2 which logs all the errors that happen on your websites.
tail -f /etc/apache2/error.log
This will list your errors on your apache websites real-time.
See the video above to know how I debugged and solved this error.
1. Install php-mbstring module
SSH into your server and type:
sudo apt-get install php-mbstring sudo service apache2 reload sudo service apache2 restart
This will install the module for you and most probably will solve this issue for you.
Remember: On the video above you might have seen that doing this didn’t work right away for me. But only after continuos restart and reload of apache server. Or you might need to just reboot your server with:
Update your php.ini
First find your install php version:
Now that you know your php version, cd into your php version at:
Now, edit you php.ini
sudo apt install nano # If nano not installed on your server nano /etc/php/(php_version)/apache2/php.ini
Since you are using nano use your CTRL + W keys to find text.
Change these to:
post_max_size = 128M upload_max_filesize = 128M max_execution_time = 360
Will add more fixes… comment one below !