Be sure to have a correct phone number format in tel: link.

coin/members/templates/members/contact.html

@@ -31,7 +31,7 @@
         {% if branding.phone_number %}
         <div class="panel">
             <h3>Téléphone</h3>
-            <p><a href="tel:{{ branding.phone_number }}">{{ branding.phone_number }}</a></p>
+            <p><a href="tel:{{ branding.phone_number|cut:' ' }}">{{ branding.phone_number }}</a></p>
         </div>
         {% endif %}
     </div>