AdWords rejecting ads because of 304 "Not Modified" error?

I am trying to understand why my site is returning 304 error codes (“Not Modified”) for many of the ads that I have submitted to Google AdWords. I have just text content for many of these pages, so is it something in the wp code that is causing this error?

Here’s an example of one of the pages being rejected:
https://cbtisrael.co.il/%D7%9E%D7%9B%D7%95%D7%9F-cbt/%D7%98%D7%99%D7%A4%D7%95%D7%9C-%D7%91%D7%9E%D7%9B%D7%95%D7%9F-cbt/%D7%91%D7%99%D7%95%D7%A4%D7%99%D7%93%D7%91%D7%A7/

(The link text is also in Hebrew, but I see it works fine when I click on the ad in Google AdWords)