the line which gives the style sheet for the simple events calendar is constantly being flagged in w3c validator, its my only error for my homepage and i cannot understand how to fix this, can someone please advise?
the line being flagged:
<link rel='stylesheet' id='sec-styling-css' href='http://vintagebonbon.co.uk/wp-content/plugins/simple-events-calendar/simple-events-calendar.css?ver=1.3.4' type='text/css' media='all' />
W3C validator error message
Error Line 489, Column 199: Element link is missing required attribute property. …s-calendar/simple-events-calendar.css?ver=1.3.4' type='text/css' media='all' /> Attributes for element link: Global attributes href crossorigin rel media hreflang type sizes Also, the title attribute has special semantics on this element.
my site link: