The HTTP request to *.svc has exceeded the allotted timeout. The time allotted to this operation may have been a portion of a longer timeout.

I imagine the issue is not that your ReceiveTimeout is beyond the maximum value for that setting, as the MaxValue of a TimeSpan is over 10 million days. Instead, I think the settings are just not taking effect.

You should try increasing the timeout values on both the server and the client-side:

On the server (in your web.config)

<binding name="customBinding0" receiveTimeout="00:10:00" sendTimeout="00:10:00" openTimeout="00:10:00" closeTimeout="00:10:00">

On the client (in your ServiceReferences.ClientConfig)

<binding name="CustomBinding_DesignOnDemandService" receiveTimeout="00:10:00" sendTimeout="00:10:00" openTimeout="00:10:00" closeTimeout="00:10:00">

The HTTP request to has exceeded the allotted timeout. The time allotted to this operation may have been a portion of a longer timeout.

Three places to set time values to fix this issue…

1. Web.Config

   <httpRuntime executionTimeout="600" />
   

   (this is seconds, so here it’s 10min). More info on httpRuntime here.

2. On your Web.Config Binding Elements

   <binding name="customBinding123"     receiveTimeout="00:10:00"     sendTimeout="00:10:00"     openTimeout="00:10:00"     closeTimeout="00:10:00" />
   

3. On your ServerReferences.ClientConfig binding elements within the system.serviceModel

   <binding name="CustomBinding"     receiveTimeout="00:10:00"     sendTimeout="00:10:00"     openTimeout="00:10:00"     closeTimeout="00:10:00" />