You may face problems with 404 errors or not found pages and Custom Post Types. Try the following steps:
- Make sure that none of your Custom Post Types and Single pages have the same name. If they do, rename the single page, including the Slug.
- Log into your WordPress Administration Screens, navigate to Settings > Permalinks. Select the default permalinks and Save. Then re-select your preferred permalinks. This will Flush the rewrite rules and should solve your problem.