JSON (1 Viewer)

Can anyone help with resolving an isuue with JSON, please?

Each time I try to open a link to a site (it's Ancestry.co.uk) a blank page opens instead with the snip shown below in the top left hand corner:


I've tried Googling for a solution but, frankly, don't understand the proposals.

Can anyone help, please?

Thank you both. I cleared history, did F12 ( which brought up a load of data, including the Ancestry.co.uk link with ‘json’ sitting at the end but no idea how to correct it. Lots of google searches but seems l either need to be a developer or take it to my local tech guy.