Breadcrumbs issues detected

Hi,
I had an email from Google Search Console saying:

Search Console has identified that your site is affected by 1 Breadcrumbs issues:
Top Errors
Errors can prevent your page or feature from appearing in Search results. The following errors were found on your site:
Invalid URL in field ‘id’

I have seen people saying to log on to WordPress – customize – theme options – disable breadcrumbs, but on my WordPress site this option isn’t there. I’m using the Sinatra theme.

Does anybody know how I can fix this?

Thanks in advance.

The page I need help with: [log in to see the link]