Warning: Trying to access array offset on value of type null in /customers/1/6/9/sailcentremakkum.nl/httpd.www/friksbeheer/wp-content/plugins/YachtFocus_yachtpresentation-visual-editor/class.yfyachts.php on line 767

Fatal error: Uncaught TypeError: Unsupported operand types: string + int in /customers/1/6/9/sailcentremakkum.nl/httpd.www/friksbeheer/wp-content/plugins/YachtFocus_yachtpresentation-visual-editor/class.yfyachts.php:1564
Stack trace:
#0 /customers/1/6/9/sailcentremakkum.nl/httpd.www/friksbeheer/wp-content/plugins/YachtFocus_yachtpresentation-visual-editor/class.yfyachts.php(1486): YF_Yachts->generateImageSlider(Array)
#1 /customers/1/6/9/sailcentremakkum.nl/httpd.www/friksbeheer/wp-content/plugins/YachtFocus_yachtpresentation-visual-editor/Yachtfocus_yachtpresentation.php(119): YF_Yachts->generate_detailpage()
#2 /customers/1/6/9/sailcentremakkum.nl/httpd.www/friksbeheer/wp-includes/class-wp-hook.php(303): yf_main_function(Object(WP))
#3 /customers/1/6/9/sailcentremakkum.nl/httpd.www/friksbeheer/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters(NULL, Array)
#4 /customers/1/6/9/sailcentremakkum.nl/httpd.www/friksbeheer/wp-includes/plugin.php(518): WP_Hook->do_action(Array)
#5 /customers/1/6/9/sailcentremakkum.nl/httpd.www/friksbeheer/wp-includes/class-wp.php(763): do_action_ref_array('wp', Array)
#6 /customers/1/6/9/sailcentremakkum.nl/httpd.www/friksbeheer/wp-includes/functions.php(1291): WP->main('')
#7 /customers/1/6/9/sailcentremakkum.nl/httpd.www/friksbeheer/wp-blog-header.php(16): wp()
#8 /customers/1/6/9/sailcentremakkum.nl/httpd.www/index.php(17): require('/customers/1/6/...')
#9 {main}
  thrown in /customers/1/6/9/sailcentremakkum.nl/httpd.www/friksbeheer/wp-content/plugins/YachtFocus_yachtpresentation-visual-editor/class.yfyachts.php on line 1564