Hey @Lukas_Iselin,
Just to be sure: did you also set up the “Connect to Custom IPs” field in AbleSet’s AbleNet settings? Even though your computers already have static IPs, AbleSet still needs to be explicitly told where to find the other hosts. Each computer should have the IPs of the other two entered there (comma-separated).
Also, before trying again, please make sure all three computers are running the latest version of AbleSet.
If things still aren’t working after that, could you create a Log Package on the computer that’s not receiving the MIDI commands? You can do that by clicking the gear icon in AbleSet’s menu bar and selecting “Create Log Package”. Please include your .als file as well (no audio needed) and upload everything to AbleSet’s Support Inbox.
I’m looking forward to your reply!