I’ve moved your post over to its own topic, @Olivier_Binet. We can help you take a look at these troubles here!
So we can better assist you, please provide a brief description of your current setup using this link as a guide.
Make sure to describe your network configuration/topology, including any networking hardware currently in use, so we can have a clear understanding of how your devices are communicating.
How often would you say this is occurring? Have you noticed any patterns? Does it seem to happen with any specific types of files or anything like that?