Installed vShare server requirements and vShare script on Centos 7 server. After installation, website showed the following error:

This page isn’t working
sitename is currently unable to handle this request.

So checked apache errors at /var/log/httpd.error_log

PHP Fatal error:  Uncaught Error: Call to undefined function simplexml_load_file() in /var/www/html/admin/home.php:93\nStack trace:\n#0 {main}\n  thrown in /var/www/html/admin/home.php on line 93,

I fixed it by installing php-xml

yum --enablerepo remi install php-xml

SimpleXML listed by php -m

$ php -m | grep -i simple
SimpleXML

Another error was

PHP Fatal error:  Uncaught Error: Call to undefined function mb_strlen() in /var/www/html/include/functions.php:393\nStack trace:\n#0 /var/www/html/upload.php(43): strlen_uni('test video')\n#1 {main}\n  thrown in /var/www/html/include/functions.php on line 393,

That was fixed by installing mbstring

yum install php-mbstring

Installaition verified using below command

php -m | grep mbstring

and restarted server

service httpd restart

The below error fixed by setting 777 permission to HTMLPurifier folder

PHP Warning:  Directory /var/www/html/include/htmlpurifier/HTMLPurifier/DefinitionCache/Serializer not writable, please alter file permissions in /var/www/html/include/htmlpurifier/HTMLPurifier/DefinitionCache/Serializer.php on line 278