SQLSTATE[HY000] [2002] Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2) on line 267 in /var/www/vhosts/iam.webserious.com/htdocs/lib/model.php

Printing Stack Trace:
#0 /var/www/vhosts/iam.webserious.com/htdocs/lib/model.php(278): Model->makeConnection()
#1 /var/www/vhosts/iam.webserious.com/htdocs/lib/model.php(117): Model->lazyConnect()
#2 /var/www/vhosts/iam.webserious.com/htdocs/components/record/record.php(655): Model->query('SELECT `value` ...', Array)
#3 /var/www/vhosts/iam.webserious.com/htdocs/components/session/session.php(233): Record->fetch()
#4 [internal function]: Session->sessionSelect('ncm4nfidl3gm1nb...')
#5 /var/www/vhosts/iam.webserious.com/htdocs/components/session/session.php(170): session_start()
#6 /var/www/vhosts/iam.webserious.com/htdocs/components/session/session.php(37): Session->sessionSet(1800, 'sessions', 'id', 'expire', 'value', 'blesta_sid')
#7 [internal function]: Session->__construct()
#8 [internal function]: ReflectionClass->newInstance()
#9 /var/www/vhosts/iam.webserious.com/htdocs/lib/loader.php(211): call_user_func_array(Array, Array)
#10 /var/www/vhosts/iam.webserious.com/htdocs/lib/loader.php(85): Loader::loadAndInitialize(Object(Main), 'component', Array)
#11 /var/www/vhosts/iam.webserious.com/htdocs/lib/controller.php(117): Loader::loadComponents(Object(Main), Array)
#12 /var/www/vhosts/iam.webserious.com/htdocs/app/app_controller.php(0): Controller->components()
#13 /var/www/vhosts/iam.webserious.com/htdocs/plugins/cms/cms_controller.php(14): AppController->preAction()
#14 /var/www/vhosts/iam.webserious.com/htdocs/plugins/cms/controllers/main.php(17): CmsController->preAction()
#15 /var/www/vhosts/iam.webserious.com/htdocs/lib/dispatcher.php(102): Main->preAction()
#16 /var/www/vhosts/iam.webserious.com/htdocs/index.php(21): Dispatcher::dispatch('/sitemap.xml')
#17 {main}