The embed code you’re adding to your web page should look something like this:
<a class="twitter-timeline" href="https://twitter.com/MaykitEvents" data-widget-id="664556271006171136">Tweets by @MaykitEvents</a>
<script src="https://platform.twitter.com/widgets.js" async></script>
You can get this embed code by creating a timeline widget at https://twitter.com/settings/widgets. Can you confirm this is what you’re doing?
Also, are you seeing this problem in all browsers?