This collection already contains an address with scheme http.  There can be at most one address per scheme in this collection.

I found in documentation prefixfilters which allow the use of ado.net dataservice with multiple host headers on website. There must be some setting in web.config like

<system.serviceModel>
<serviceHostingEnvironment aspNetCompatibilityEnabled="true">
<baseAddressPrefixFilters>
<add prefix=http://www.yourdomain.com/>
</baseAddressPrefixFilters>
</serviceHostingEnvironment>
</system.serviceModel>
</configuration>