Page Cache is detected but server response is still low

Good Afternoon,

I have read a few post with same title but I don’t seem to get an answer on what I should do.

My site Health is telling me I have 1 critical issue:

Page Cache is detected but server response is still low

Page cache enhances the speed and performance of your site by saving and serving static pages instead of calling for a page every time a user visits.

Page cache is detected by looking for an active page cache plugin as well as making three requests to the homepage and looking for one or more of the following HTTP client caching response headers:

cache-control, expires, age, last-modified, etag, x-cache-enabled, x-cache-disabled, x-srcache-store-status, x-srcache-fetch-status, x-litespeed-cache, x-lsadc-cache, x-qc-cache.
Median server response time was 1,052 milliseconds. It should be less than the recommended 600 milliseconds threshold.
There were 3 client caching response headers detected: etag, x-litespeed-cache, age.

Can you help me resolve this.

The page I need help with: [log in to see the link]