Guestbook signup error php5.6 (Website created with RVsitebuilder 5)

Problem:
Cannot open sign guestbook.

To check Problem/Error:

You can check the error_log in cPanel -> File Manager:

/home/{domain-name}/public_html/error_log

It will show error:

PHP Parse error: syntax error, unexpected 'new' (T_NEW) in /opt/cpanel/ea-php73/root/usr/share/pear/HTML/QuickForm.php on line 601

Solution:
Change PHP version your domain to PHP5.6
cPanel -> MultiPHP Manager -> Set PHP Version per Domain and "Apply"

Result of your Guestbook now.
Show

Sign