How do I fix a “Request format is unrecognized for URL…” error in a web service running in IIS?

Since HTTP GET and HTTP POST are disabled by default try adding the following to your config file:

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