External broken links:
Google search console does not warn webmasters when there is a broken link pointing to an external website on one or several pages. However, this is a google juice leakage and a bad experience for visitors.
Iframe that does not work:
We don’t recall any crawling errors from Google search console to mention that an Iframe (hosted on our website or outside of our website) wasn’t working.
Images hosted on a different server:
When the domain of the image URL isn’t the domain of the website, it looks like Google search console does not report such an issue.
The Sitecozy broken link checker application reviews the links for all these types of errors and generate a report listing every single error related to external broken links, broken iframe urls and broken image urls.