Header says no caching and expire date in the past

[capeinfo]

Hi

My site uses joomla caching and jch optimise, but looking at the headers I see the following:

header.png

How can I rectify this?
Thanks

[waarnemer]

Since you are using a CMS that creates dynamic pages, by default the generated PHP is not to be cached by your browser.

Static content such as css, jpg, js and on can and will usually be cached.

Read more on: https://docs.joomla.org/Cache and there is a huge bunch more written on cache mechanisms throughout the web.

Beware optimizers that shrink and combine scripts have the scripts generated and therefore may have odd epiry dates on those too.
Do read the documentation thoroughly. JCH has very good documentation. Good configuration can help, bad config is just slowing your site.