diff --git a/DNN Platform/Library/Common/Utilities/UrlUtils.cs b/DNN Platform/Library/Common/Utilities/UrlUtils.cs
index 545ce9b5bfd..45b673fd3b9 100644
--- a/DNN Platform/Library/Common/Utilities/UrlUtils.cs	
+++ b/DNN Platform/Library/Common/Utilities/UrlUtils.cs	
@@ -400,6 +400,11 @@ public static bool InPopUp()
             return HttpContext.Current != null && HttpContext.Current.Request.Url.ToString().IndexOf("popUp=true", StringComparison.OrdinalIgnoreCase) >= 0;
         }
 
+        public static bool IsPopUp(string url)
+        {
+            return url .IndexOf("popUp=true", StringComparison.OrdinalIgnoreCase) >= 0;
+        }
+
         /// <summary>
         /// Redirect current response to 404 error page or output 404 content if error page not defined.
         /// </summary>
diff --git a/DNN Platform/Library/Entities/Urls/AdvancedUrlRewriter.cs b/DNN Platform/Library/Entities/Urls/AdvancedUrlRewriter.cs
index 8604a5fdd95..830cdb2ece5 100644
--- a/DNN Platform/Library/Entities/Urls/AdvancedUrlRewriter.cs	
+++ b/DNN Platform/Library/Entities/Urls/AdvancedUrlRewriter.cs	
@@ -1554,8 +1554,11 @@ private bool CheckForSecureRedirect(PortalSettings portalSettings,
                     //check ssl enforced
                     if (portalSettings.SSLEnforced)
                     {
-                        //check page is not secure, connection is secure
-                        if (!portalSettings.ActiveTab.IsSecure && result.IsSecureConnection)
+                        // Prevent browser's mixed-content error in case we open a secure PopUp or a secure iframe 
+                        // from an unsecure page
+                        if (!portalSettings.ActiveTab.IsSecure && 
+                            result.IsSecureConnection &&
+                            !UrlUtils.IsPopUp(url))
                         {
                             //has connection already been forced to secure?
                             if (queryStringCol["ssl"] == null)