Template Error

Impossible to access an attribute ("url") on a null variable.

/home/forge/stage.uscj.org/craft/templates/connect/_layout.twig(36)

24     height: 200,
25     zoom: 14,
26     draggable: false,
27     disableDefaultUI:true
28 } %}
29 
30 
31 
32 {% block content %}
33 
34 <div class="container">
35   <ol class="breadcrumb">
36     <li class="breadcrumb-item"><a href="{{parentSingle.url}}">{{parentSingle.title}}</a></li>
37    </ol>
38 
39     <h1 class="page-heading mb-1">{{ entry.title }}</h1>
40         <h4 class="mt-0 mb-2">
41         {% if entry.multiDay %}
42 
43             <span class="text-danger mr-1">
44                 {% if entry.startDate.format("Y") != entry.endDate.format("Y") %}
45                     {{ entry.startDate.format("F j, Y")}}&thinsp;&ndash;&thinsp;{{ entry.endDate.format("F j, Y")}}
46                 {% elseif entry.startDate.format("F") != entry.endDate.format("F") %}
47                     {{ entry.startDate.format("F j")}}&thinsp;&ndash;&thinsp;{{ entry.endDate.format("F j, Y")}}
48                 {% else %}
2024-03-28 15:59:43 nginx/1.15.8 / Craft CMS 2.7.2