Slide in not appearing and shows 404 error when previewed


I am trying to add a slide in CTA to my homepage, but it is not appearing. When I try to preview the Slide in in the editor, I get a 404 page not found error.

I want to use this html:
<!--HubSpot Call-to-Action Code -->
<span class="hs-cta-wrapper" id="hs-cta-wrapper-1cd3cd45-9fa4-46de-9bbd-fd23a47df591">
<span class="hs-cta-node hs-cta-1cd3cd45-9fa4-46de-9bbd-fd23a47df591" id="hs-cta-1cd3cd45-9fa4-46de-9bbd-fd23a47df591">
<!--[if lte IE 8]><div id="hs-cta-ie-element"></div><![endif]-->
<img class="hs-cta-img" id="hs-cta-img-1cd3cd45-9fa4-46de-9bbd-fd23a47df591" style="border-width:0px;" src="" alt="Don't miss early-bird pricing! Register now for the 2015 LERN Annual Conference Dec. 2-5, New Orleans"/>
<script charset="utf-8" src=""></script>
<script type="text/javascript">
hbspt.cta.load(119076, '1cd3cd45-9fa4-46de-9bbd-fd23a47df591');
<!-- end HubSpot Call-to-Action Code -->