Improve error message based on merge request review.

www/src/doiview.js

@@ -109,9 +109,9 @@ DOIView.prototype.renderError = function (jqXHR, errorThrown, origin) {
         }
     } else {
         if (origin === "welcome-page") {
-            message = "<h3> Not found ! </h3> <p> Connexion problem to the server. </p>";
+            message = "<h3> Not found ! </h3> <p> Connexion problem to the datacite server. Please try again later.</p>";
         } else {
-            message = "<h2> Not found ! </h2> <p> Connexion problem to the server. </p>";
+            message = "<h2> Not found ! </h2> <p> Connexion problem to the datacite server. Please try again later.</p>";
         }
     }
     dust.render(template, {