Strange plugin behavior in Ableton. Loses ability to "hear" midi instrument

So my plugin is a midi effect plugin. When I first load it on a track, it receives input from my midi keyboard without any problems. When I route the midi output to another track to control another instrument, I can confirm that midi output is still working but I no longer receive input from my midi keyboard. Any ideas as to why it would stop hearing my instrument?

Thanks!

Edit: Nevermind! I figured it out. I’ll letve this up in case it helps somebody else, but my track was becoming unarmed. It looks like both tracks need to be armed for it to work.