When updates are made for WordPress the page is placed in a maintenance mode to inform the visitor that the page exists but is currently performing maintenance. This usually leaves within a minute but sometimes it happens that maintenance mode sticks and does not expose your page but you can easily fix it on your own.
You need your FTP application and your FTP user information to connect through us.
Click here to see our guides regarding FTP.
Once you have connected via your FTP application then click on the installation of WordPress and then look for the “.maintenance” file in the root of the installation and remove the file. You should then be able to reload your WordPress page after the error message has disappeared and your page should be displayed as before.