Amazon Affiliate "strip" links disappeared

I was “off” my website for the holidays. When I came back in January, I updated to both the most recent version of WordPress and the most recent version of Graphene (theme). Problem: My Amazon Associates links have disappeared, and when I try to add new ones, they do not show up. I have chosen to add a “text only” link to new ads until this is fixed (those still work).

My site is http://HorrorHouseParty.com.

You can see a “disappeared” code here:
http://horrorhouseparty.com/news/2015/10/01/chomp-spoiler-free/

You can see my “workaround” here:
http://horrorhouseparty.com/kidsnews/2016/01/06/zoolander-at-15-a-good-looking-work-of-art/

The original code that disappeared is:

<iframe style="width:120px;height:240px;" marginwidth="0" marginheight="0" scrolling="no" frameborder="0" src="//ws-na.amazon-adsystem.com/widgets/q?ServiceVersion=20070822&OneJS=1&Operation=GetAdHtml&MarketPlace=US&source=ac&ref=tf_til&ad_type=product_link&tracking_id=horhoupar-20&marketplace=amazon&region=US&placement=B00BI7BLXE&asins=B00BI7BLXE&linkId=ZZL27WCUFSR23COG&show_border=true&link_opens_in_new_window=true">
</iframe>

I do not see anyone else with this problem (now, anyway), so it may be idiosyncratic. Thank you for any help.