If this error is not persistent, if it happens sometimes, it looks like a resource that RFA app needs, for example connectivity to EZD, DLL access, sufficient CPU or memory, becomes briefly unavailable to the app.
Once the availability of the resource is restored, RFA app will proceed as expected.
Does this happen at predictable times? If this is the case you may be able to figure out what causes the resource lock. I.e. market peak, or machine load peak due to other heavy jobs being run.