El detalle del error mostrado por IIS es:
Memory gates checking failed because the free memory (373817344 bytes) is less than 5% of total memory. As a result, the service will not be available for incoming requests. To resolve this, either reduce the load on the machine or adjust the value of minFreeMemoryPercentageToActivateService on the serviceHostingEnvironment config element.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.InsufficientMemoryException: Memory gates checking failed because the free memory (373817344 bytes) is less than 5% of total memory. As a result, the service will not be available for incoming requests. To resolve this, either reduce the load on the machine or adjust the value of minFreeMemoryPercentageToActivateService on the serviceHostingEnvironment config element
Se ha solucionado añadiendo las siguientes lineas en el web config de la aplicación
<system.serviceModel>
<serviceHostingEnvironment minFreeMemoryPercentageToActivateService="0" />
</system.serviceModel>