This sounds like the mathjax issues discussed a few times previously on these forums and on the mailing lists. What version and revision are you using? Get whoever looks after your installation to check the following:
MathJax changed their MathJax CDN hosting. Specifically they changed the https:// address we use in Xerte Online Toolkits. You can read more about that change here:
www.mathjax.org/changes-to-the-mathjax-cdn/
There are 3 files in the Xerte install which point to the now broken source.
The 2.1 distribution, and 2.1 update packages are fixed.
You can also patch your installation:
These are the files that need fixing:
\modules\site\play.php
\modules\site\preview.php
\modules\xerte\player_html5\rloObject.htm
The change needed is to change
<script type="text/javascript" src="c328740.ssl.cf1.rackcdn.com/mathjax/late...ML-AM_HTMLorMML-full"></script>
to
<script type="text/javascript"
src="//cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
</script>
HTH
Ron
