Suddenly the first page of this long established site does not appear to change to responsive on an iPhone 11.
Ruby theme. https://www.janehamiltonfineart.com
The attached screenshots are the site on an iPhone.
And the same page when dragged to a small size in Safari on a computer.
looks like you are getting a 400 error. Looks like you have done something to the theme base code? Looks like the Google fonts statement has a syntax error.
You have NO valid viewport statement, looks like you may have over-written it with somw kind of Domain verify code?