It looks like a poorly coded hosting-side protection.
I say poorly coded because “WordPress” is misspelled and it uses <script language="javascript">
.
Ask your host. This is definitely not WordPress native behaviour.
Also, check your document root, as the file seems to be self-contained. It might be an extra HTML file in your document root. Use your hosting panel File Manager, or an (S)FTP app, such as WinSCP or FileZilla.