Error Invalid or Empty Node passed to getItem constructor

I’m getting this error on a site when trying to view it:

Invalid or Empty Node passed to getItem constructor.

I’ve read this is to do with page drafts but this is happening on viewing the site so I can’t login or see any pages. Never seen it before and the only forum posts on this are to do with indexing search engine… can anyone advise on how to fix it or what it means?

It’s version 8.7.5.10
thanks

@WebOnTheWebb
What happens if you go to yourwebsite.com/index.php/login? Do you get an alert page with the error? Are you able to upload a screenshot of the error?

Hi Jes. Better still, it’s at www.dementiamatterspowys.org.uk

No idea what this error is but I’m considering updating C5 to fix it… unless you have other ideas?
J

I did find a mixed content issue that might be contributing.

Thanks. Yeah, that needs fixing but I don’t think that’s related… it must have been like that for a while and this is a new error
J