diff --git a/plugins/poll/assets/javascripts/controllers/poll-ui-builder.js.es6 b/plugins/poll/assets/javascripts/controllers/poll-ui-builder.js.es6
index ab97861dfce..e5f1c83148e 100644
--- a/plugins/poll/assets/javascripts/controllers/poll-ui-builder.js.es6
+++ b/plugins/poll/assets/javascripts/controllers/poll-ui-builder.js.es6
@@ -118,7 +118,10 @@ export default Ember.Controller.extend({
     if (pollMax) pollHeader += ` max=${pollMax}`;
     if (isNumber) pollHeader += ` step=${step}`;
     if (publicPoll) pollHeader += ` public=true`;
-    if (autoClose) pollHeader += ` close=${moment(date + " " + time, "YYYY-MM-DD HH:mm").toISOString()}`;
+    if (autoClose) {
+      let closeDate = moment(date + " " + time, "YYYY-MM-DD HH:mm").toISOString();
+      if (closeDate) pollHeader += ` close=${closeDate}`;
+    }
 
     pollHeader += ']';
     output += `${pollHeader}\n`;
@@ -186,7 +189,7 @@ export default Ember.Controller.extend({
       pollMax: null,
       pollStep: 1,
       autoClose: false,
-      date: moment().add(1, "day").format("YYYY-DD-MM"),
+      date: moment().add(1, "day").format("YYYY-MM-DD"),
       time: moment().add(1, "hour").format("HH:mm"),
     });
   },
diff --git a/plugins/poll/assets/javascripts/widgets/discourse-poll.js.es6 b/plugins/poll/assets/javascripts/widgets/discourse-poll.js.es6
index f51c12e3add..f9d68c0a7e3 100644
--- a/plugins/poll/assets/javascripts/widgets/discourse-poll.js.es6
+++ b/plugins/poll/assets/javascripts/widgets/discourse-poll.js.es6
@@ -354,12 +354,14 @@ createWidget('discourse-poll-info', {
 
       if (poll.close) {
         const closeDate = moment.utc(poll.close);
-        const title = closeDate.format("LLL");
-        const timeLeft = moment().to(closeDate.local(), true);
+        if (closeDate.isValid()) {
+          const title = closeDate.format("LLL");
+          const timeLeft = moment().to(closeDate.local(), true);
 
-        result.push(new RawHtml({
-          html: `<span class="info-text" title="${title}">${I18n.t("poll.automatic_close.closes_in", { timeLeft })}</span>`
-        }));
+          result.push(new RawHtml({
+            html: `<span class="info-text" title="${title}">${I18n.t("poll.automatic_close.closes_in", { timeLeft })}</span>`
+          }));
+        }
       }
     }