Adding featured images to month view

Hello, I implemented this https://theeventscalendar.com/knowledgebase/adding-featured-images-to-month-view/ in my calendar. It works but if there is an image, I am unable to click on the event to view more details. But if there isn’t an image, i can click on it and it works. Is the code in the site mentioned inaccurate or do i have to do additional CSS to make it work?

Thank you :)!

https://wordpress.org/plugins/the-events-calendar/