I can’t get this to work, and I get this message in Chrome:

Creating Application Cache with manifest https://www.riisdesign.no/wp-content/themes/riisdesign-business/cache.manifest
Application Cache Checking event
Application Cache Error event: Manifest fetch failed (-1) https://www.riisdesign.no/wp-content/themes/riisdesign-business/cache.manifest

The link to my website is: https://riisdesign.no/

Any suggestions?

https://www.ads-software.com/extend/plugins/cache-manifest-for-wordpress-themes/

I installed the plugin exactly as instructed. The file was automatically created in my wordpress directory by the plugin. I visited the website in many different browsers. Then I disconnected my internet connection and the pages were no longer available offline.

https://www.ads-software.com/extend/plugins/cache-manifest-for-wordpress-themes/