That error is from a WCF throttle to avoid taking new server calls when your box is ‘low on memory’. You can set the throttle to what percent you want with 0 being no throttle:
<system.serviceModel>
<serviceHostingEnvironment minFreeMemoryPercentageToActivateService="0" />
</system.serviceModel>
The intent was valid - to not have a deluge of calls overwhelming the server so it cannot respond and everything is stuck paging to disk constantly. Now that we normally have servers near or above triple digits of RAM, 5% is a huge chunk of memory 
Just set it to 1 or 0 and you will be happier.