Template Error

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

/home/thewoolist/craft/templates/sheep/_entry.html(133)

121                         </div>
122 
123                     </div>
124 
125                     <div class="row flex">
126 
127                         <div class="columns small-12 medium-4">
128 
129                             <div class="slideshow" data-slideshow-type="text-image" data-mh="slideshow-section">
130 
131                                 {% for row in block.slide %}
132 
133                                     <div class="slide bg-image bg-cover" style="background-image: url({{ row.image.first().url }})"></div>
134 
135                                 {% endfor %}
136 
137                             </div>
138 
139                         </div>
140 
141                         <div class="columns small-12 medium-8 xlarge-6 end">
142 
143                             <div class="height-size-full slideshow-align" data-mh="slideshow-section">
144 
145                                 <div class="slideshow margin-bottom-medium" data-slideshow-type="text-image">
2024-03-28 18:31:24 Apache / Craft CMS 2.6.2983