The page is not displayed at all and the error is as follow:

“Error: at line 134 in file /site/lib/classes/class.CMSModule.php: _hidden is
not a gettable property of CMSModule”

Trace: 
#0 /site/assets/modules/CGHeadMaster/CGHeadMaster.module.php(343):
CMSModule->__get('_hidden')
#1 /site/assets/modules/CGHeadMaster/CGHeadMaster.module.php(361):
CGHeadMaster->is_hidden('canonical')
#2 /site/assets/modules/CGHeadMaster/lib/class.smarty_plugins.php(97):
CGHeadMaster->render_field('canonical')
#3
/site/tmp/templates_c/3c58319361c030c4cdb498d3f4cefe11^41e472b4fe74440314a6a33a268fae7bfb00cf95_0.cms_theme.ccscmbccscmbpagestd.tpl.php(39):
CGHeadMaster\smarty_plugins::cghm_render(Array,
Object(CMSMS\internal\template_wrapper))
#4
/site/lib/vendor/smarty/smarty/libs/sysplugins/smarty_template_resource_base.php(123):
content_5dd30546313868_42360948(Object(CMSMS\internal\template_wrapper))
#5
/site/lib/vendor/smarty/smarty/libs/sysplugins/smarty_template_compiled.php(114):
Smarty_Template_Resource_Base->getRenderedTemplateCode(Object(CMSMS\internal\template_wrapper))
#6
/site/lib/vendor/smarty/smarty/libs/sysplugins/smarty_internal_template.php(216):
Smarty_Template_Compiled->render(Object(CMSMS\internal\template_wrapper))
#7
/site/lib/vendor/smarty/smarty/libs/sysplugins/smarty_internal_templatebase.php(232):
Smarty_Internal_Template->render(false, 0)
#8
/site/lib/vendor/smarty/smarty/libs/sysplugins/smarty_internal_templatebase.php(116):
Smarty_Internal_TemplateBase->_execute(Object(CMSMS\internal\template_wrapper),
NULL, NULL, NULL, 0)
#9 /site/lib/classes/internal/class.template_wrapper.php(27):
Smarty_Internal_TemplateBase->fetch(NULL, NULL, NULL, NULL)
#10 /site/index.php(202): CMSMS\internal\template_wrapper->fetch()
#11 {main}