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.
Note:
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.