Error CodeIgniter and base url, inclusion of: 80 in http

I have a CodeIgniter application with PHP, in IIS 7.0.

Use the base-url in the CodeIgniter config.

When I call any topic in the app, it inserts the ": 80" and it does not find the url.

Example: http: //: 80 / HTTP Error 404.0 Not Found occurs.

Any ideas that might help? Thank you