There are two common reasons why a website would be moved to a new domain. One is that the website's current domain is technically insufficient for its needs; this can happen because the domain is located on a hosting server that features slow reaction times and causes browsers to load its relevant content more slowly. Likewise, the business may have rebranded, in which case it would only make sense for the website's URL to reflect the new name of the business the same way the content displayed in the window now presumably would. The other primary reason is that the business owning the website may be merging with another business focused on the same industry. Even if this business was once a competitor, there would be little logic in the two websites existing as separate entities if the newly merged corporation does business under the same roof. In any of these cases, one of the most important steps any business can take with its newly relocated website is to make sure that the URLs of the original site and all of its respective pages host 301 redirects pointing to the URLs corresponding to where the website is located now. If a website has relocated while retaining its structure and layout, 301 redirects are needed to instruct Google not to discard the website's prior prominence in SERPs. If the URLs that once had content pages that ranked highly in Google are empty, they will return 404 error messages instead, and Google will consider the moved pages to be "new" pages that are only now starting to accumulate ranking credit. Even if a website merges with another in such a way that the other website should not expect to receive its ranking credit, leaving behind 301 redirects is still important because Internet users may nonetheless end up at those URLs looking for the content associated with the original website. Being shown an error screen otherwise could literally prevent viewers from being aware that the website merged with another company and leave them speculating about a potentially dire fate for the website instead. For more information click here https://www.reddit.com/r/SEO/comments/9y8w3d/404errorisfoundonthedomainofthe_company/.