Sending ArtNet using Localhost stopped working in macOS 26

[lightupyourmind]

I used artnet using the Localhost for sending DMX between two softwares, running on the same machine (QLC+ and Arena). It worked like a charm until I updated my Mac to macOS 26. I guess the update is the problem, I did not changed anything else. Arena shows the error: sendmsg failed: no route to host
in QLC+ there is the ArtneNode of my Arena instance visible for a short period of time after activating it in Arena, but it can't recieve any dmx data and disappears after some minutes.
Any suggestions how to solve this problem? I got a gig on friday and am starting to worry a bit...

All the best!

[Zoltán]

Shared port handling might have changed.
The issue is you send and receive on the same port, which can't be bound by two apps at the same time.
You'd need two separate network cards connected to the same network, one could be wifi, then use one in one app, and the other in the other app.

Or run one of the apps in a VM