This is common when accessing the "CMS" as http://localhost. If you are doing this then you should try http://127.0.0.1 instead.
If you are interesting in the details on why this happens then read below.
Spoiler:
Windows Vista and later support IPv6 by default and Apache is often configured to bind to IPv6 if it can. However, pretty much all emulators only support IPv4.
When you access http://localhost then Windows will resolve localhost as IPv6 to "::1". When the client then connects to the emulator on localhost Windows resolves as IPv4 to "127.0.0.1". The emulator then compares the IP it is connecting from (127.0.0.1) and the IP in the database (::1) and terminates the connection as they don't match.
By using http://127.0.0.1 you skip Windows resolving localhost and so the database contains "127.0.0.1" meaning they match and the connection is authenticated.
Just to be clear, this is not always the cause but it is sometimes. And as it so simple to work around and doesn't cause any problems with live hotels it is worth a try.
