A lot of companies with website don’t think ahead in the case of website issues. An easy page that should always be set up for that terrible moment if the site goes down – the maintenance page.
404 errors is a negative experience for your visitors. For all they know the site is down for good.
With a clear generic maintenance page ready, your visitors will know it is only temporary, you are looking into it AND they can come back later and know you should be up.
Click here for some great examples of maintenance pages.