Hi Martin. I'm Greg, an eleven years awarded MVP, Volunteer Moderator, and Independent Advisor here to help you until this is resolved.
When you create a network via ethernet crossover cable, either it will work or the wireless network but usually not both. When I have done this in the past to transfer files between two PC's, I had to shut of wireless to get the PC's to connect to each other.
Read more about ad hoc networks:
https://www.lifewire.com/set-up-an-ad-hoc-peer-...
https://www.quora.com/How-can-you-network-two-W...
I hope this helps. Based on what you report back I can answer any questions and may have other steps to perform. If you'll wait to rate whether my post was helpful, I will keep working with you until it's resolved.
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