Problem with home page and plugin

I upgraded to WordPress 4.5.2 and upgraded the plugin to 7.2.3. Now my site homepage will not load (www.candcsoftware.com). My ISP investigated and wrote back:

A plugin seems to be the cause of the redirect issue. We found in our
error logs referenced to HEAD requests from browser agents, then immediately followed by a call for “index.html”. After searching through subdirectories at the base web level, we found plugin “Custom Permalinks” had an included index.html file, and was downloaded or updated at the same time as other WordPress files.

After disabling the “Custom Permalinks” plugin, the home page loads, but it fouls up the rests of the site. Reactivating it breaks the home page.
Bill Buntain

https://www.ads-software.com/plugins/custom-permalinks/