Symptoms
The homepage of an IIS website with Wordpress application installed is loading correctly, but requests to any other page end with 404 error.
The following entry is represented in the website log:
2017-01-02 12:12:13 GET /somelink/ 203.0.113.2 HTTP/1.1 Mozilla/5.0+(Windows+NT+10.0;+Win64;+x64;+rv:52.0)+Gecko/20100101+Firefox/52.0 http://www.example.com/ somelink 404 0 291
Cause
'Permalinks' are configured in the Wordpress control panel, but 'URL rewrite' module either has not been installed or disabled on the IIS server.
Resolution
Download and instal 'URL Rewrite Module' following instructions from the Official IIS site
Enable URL rewrite:
IIS Manager > Select server > Modules > Configure native modules > Add 'RewriteModule' to the list