Fatal PHP error

Uncaught TypeError: unserialize(): Argument #1 ($data) must be of type string, array given in /homepages/12/d79699181/htdocs/extensions/News/einzel_ansicht.php:6
Stack trace:
#0 /homepages/12/d79699181/htdocs/extensions/News/einzel_ansicht.php(6): unserialize()
#1 /homepages/12/d79699181/htdocs/elemente/classes/CMS.php(627): include('/homepages/12/d...')
#2 /homepages/12/d79699181/htdocs/elemente/classes/CMS.php(562): elemente\classes\CMS->addExtension()
#3 /homepages/12/d79699181/htdocs/elemente/classes/CMS.php(481): elemente\classes\CMS->ContentRender()
#4 /homepages/12/d79699181/htdocs/elemente/classes/CMS.php(582): elemente\classes\CMS->Content()
#5 /homepages/12/d79699181/htdocs/elemente/classes/CMS.php(481): elemente\classes\CMS->ContentRender()
#6 /homepages/12/d79699181/htdocs/elemente/classes/CMS.php(332): elemente\classes\CMS->Content()
#7 /homepages/12/d79699181/htdocs/elemente/classes/CMS.php(233): elemente\classes\CMS->cmsContent()
#8 /homepages/12/d79699181/htdocs/index.php(45): elemente\classes\CMS->getCMS()
#9 {main}
thrown