On the router logs, a particular call was delivered to an available agent. But after 15 seconds, there was a message EventRemoteConnectionFailed, the caller then received a disconnected message. Would that call go to the default number llisted on the ISCCAttributeExtensions ‘DEFAULT#’ ? I tried calling the number listed on the DEFAULT#, but it just went through ok to an agent, i didn’t hear any disconnected message (number you are calling is not in service)
Sounds like a ISCC timeout (possibly from your external route points being busy). What was the time between the ISCC Route Request and the ISCC timeout? Check the TServer option under extrouter → request-tout. If this is 10 seconds, and your request-timeout events were 10 seconds appart you may need to look at configuring additional external route points, or changing the TServer setting to something larget.
From a data/targeting perspective, the agent will be found, selected and reserved, however the voice path will be unable to be paired. Not 100% sure this is your issue, but something worth looking into.
Network latency will only effect your data segment of the call. I assume you are using a PSTN transfer connect (vs. Tie lines)? 15 seconds should be suffice for your tout setting, so I would recommend configuring additional external route points to handle to load.
Once a remote agent is selected, your external route points will be reserved for 15 seconds while waiting for a call, if your calls take 10-15 seconds to arrive you could easily use all availble external route points.