Sitelock - can't open pages

I’m trying to open a client’s page but having a Sitelock screen pop up when trying to open, for example, the “About Us” page. I cannot get to the About Us page, because I’m being blocked as if in a browser.

I’ve tried disabling Javascript, but it just tells me that it’s disabled.

The page opens as editable without issues in Dreamweaver.

Any ideas?