Permalink problems can be a very annoying. The following post presents a guideline to fix the problem in a systematical way. Specifically, the post refers to the problem that pages, sites and posts of a self-hosted WordPress blog become inaccessible once one changes the permalink settings. Generally, there are various sources that can cause the same problem. Below you find a checklist that one can go through step by step to find the error.

1. .htaccess must be present in the same folder as index.php
2. .htaccess be writeable
3. apache2.conf must allow overwrite
4. database problems