When convenient
Another website can put your pages inside its own
This is the exact wording EverThread uses when it finds this on a customer's site, written for someone who runs a business, not a server. The example site here is yourbakery.com.
What we saw
Your site does not tell browsers to refuse being shown inside a frame on someone else's page.
Why it matters
Scammers use that to lay an invisible copy of your site over fake buttons, so visitors click things they cannot see.
How to fix it
Send the technical line below to whoever runs your site. Each of these is a one-line change in the server or hosting settings, and none of them changes how the site looks.
For your developer
Add X-Frame-Options: DENY (or SAMEORIGIN), or a Content-Security-Policy frame-ancestors directive.