In some situations one of these errors may appear in the log files for the Discovery client agents
In the JobQueue_GetClientTasksQueue file(s):
Soap request for client tasks failed. No soap error message available.
in the JobQueue_OutboxProcessorTasksQueue file(s):
Failed to send soap message by Client Transport web service. No soap error message available.
They will most commonly appear in the JobQueue_GetClientTasksQueue or JobQueue_OutboxProcessorTasksQueue log file(s).
This article has more details about these errors
This error can indicate an underlying http communication issue. In order to diagnose the situation further installation of the Fiddler utility to capture an HTTP/HTTPS trace is recommended.
Additionally a request with development has been made to improve the logging to relay the HTTP status code to the log files as well. Please see RM249972 for further details.
One Example of what a support found in a fiddler trace when seeing these errors in a customer environment is also detailed on KB26410