We have software that for certain clients fails to download a file. The software is developed in Python and compiled into an Windows Executable. The cause of the error is still unknown but we have established that the client has an active internet connection. We suspect that the cause is due to the clients network setup. This error cannot be replicated in house. What technique or methodology should be applied to this kind of specific error that cannot be replicated in house. The end goal is to determine the cause of this error so we can move onto the solution. For example; Remote Debugging: Produce a debug version of the software and ask the client to send back a debug output file. This involves alot of time (back and forth communication) and requires the client to work and act in a timely manor to be successful. In-house debugging: Visit the client and determine their network setup, etc. Possibly develop a series of script tests before hand to run on the clients computer under the same network. Other methodologies and techniques I am not aware of?