If your website is running on the WordPress platform then this will be quite easy as compared to others. There are two ways to solve the issue of an invalid URL. I am sure you are using an SEO Plugin for your WordPress website, normally it will be Yoast SEO due to its advanced feature and simple to use. You need to make some changes to your SEO plugin and theme. There is no need for coding, it will be quite easy to solve the issue. There are two ways to fix the breadcrumb issue. One is from SEO plugin if you are using and the other is from your theme. If your problem is solved with one method then there is no need to follow the other method. It is up to you to follow both. You can see the step by step guide to solve invalid URL in field id.