failure.html.erb in bookingsync-engine-6.0.0

- old
+ new

@@ -1,5 +1,7 @@
 <h1>Authentication failed</h1>
 
 <p>Error: <%= @error_message %></p>
 
-<a href="/auth/bookingsync">Sign in again</a>
+<%= form_tag("/auth/bookingsync", method: :post) do %>
+  <button type="submit">Sign in again</button>
+<% end %>