It is very important to check that links on your domain are linking correctly and therefor it is recommended to check them on a regular basis.
The Dashboard in OnPage.org offers a quick overview to identify if something goes wrong. If you would like to figure out which link is now broken just go to
"Zoom" -> "Links" -> "Status Codes" and click on "Add Filter" select the filter "Target (Group)" and set it to "is" "different Host". Now you can see all links we have found on your domain, that are pointing to external Domains.
Ideally, all links will point to a page with a status code 200. For all other Status codes, it is recommended to check if it is possible to change to link to a correct URL.