In February this year Google had announced that starting 30th June 2016, advertisers will no longer be able to upload flash ads.
Google will now only accept HTML5 for animated ads.
Google said on Google+:
“In February, we announced that the Google Display Network and DoubleClick Digital Marketing are now going 100% HTML5. Starting June 30th, 2016, display ads built in Flash can no longer be uploaded into AdWords and DoubleClick Digital Marketing.
AdWords advertisers who use Flash ads in their campaigns have several ways to ensure your creative can continue to show on the Google Display Network. Read more here: https://goo.gl/ZBq5DR”