If you have already tried again later and it still doesn’t work, can you please check the following:
Are you able to access your files through the file manager or FTP? If the file manager does not work, please try a desktop FTP client. If that also doesn’t work, then FTP access is not working for your account, and you’ll need to fix that first. To do that, please have a look at this article: Help, I cannot connect to FTP