Request format is unrecognized for URL unexpectedly ending in '/

When your browser gives you http 500 error while trying to connect to a web service it’s usually because you forgot to add a little something in the web config.

<configuration>
    <system.web>
    <webServices>
        <protocols>
            <add name="HttpGet"/>
            <add name="HttpPost"/>
        </protocols>
    </webServices>
    </system.web>
</configuration>

Since I was really really tired it took me 20 minutes something figuring out because I did not get this very nice error message at first!! Grrrr