The title is self explanatory. This is an Apple Silicon machine. The indexer.log file contains:
2022-06-08T11:05:53.895-07:00 [Error] EmbeddedServer.boostrap: error : Server Error : Fail to start PeerListener. err = %v : listen tcp4 :9100: bind: address already in use
Port 9100 is not in use as shown by:
lsof -nP -iTCP -sTCP:LISTEN
What must I do?
Thanks!
@Hawkeye Can you check if a firewall or similar is blocking the port? Generally when this happens it generates confusing failure messages like this. (Unfortuantely there is no “firewall is blocking the port” error message. 
)
Aaaah good idea. Alas, I checked my firewall is off.
Found it! My lsof command to check what process listens to what was too restrictive, removing the TCP:LISTEN option I find:
lghub_age 9700 vincent 31u IPv4 0xf9c8e2bbafac34f7 0t0 TCP 127.0.0.1:64720->127.0.0.1:9100 (ESTABLISHED)
Apparently Logitech loves port 9100 too… 
@Hawkeye Glad you found it. I had almost asked if you were sure your port list was good – I find this seems to be a difficult check to make reliably due to all the options and weird defaults.
Yes, you are being nice, I feel like a fool. Ahahah.
May this help somebody else who has installed some Logitech stuff.