Thank you threadi. That’s the article I read. It’s just over my head I’m afraid.
My server, Namesco, stated that it’s not a problem their end, but I will try and go back to them with this new advice.
15 years ago I set up and ran my own website very successfully. The systems have all changed dramatically now, and apparently are so much easier to set up and maintain. But this new website has given me so many problems.