Also saw that same error. Somewhere along the way, things started to work; though I'm not quite sure what single thing did it. For what it's worth: A couple of notes of what I tried (in addition to the documented steps out there):
Get a clean configuration file; and make sure it's owned by the same user that runs the asterisk application ("asterisk"user and group).
bash $ sudo rm /etc/asterisk/echolink.conf
bash $ sudo cp /usr/share/doc/asl3-asterisk-config/examples/configs/asl3/echolink.conf /etc/asteriskbash $ chown asterisk: /etc/asterisk/echolink.conf
Carefully edit the config file. My not doing so contributed to my issues.
After enabling the module (/etc/asterisk/module.conf), I opted to restart the server entirely (probably overkill; but why not).
You can also try to manually load it in Asterisk CLI.
CLI> module load chan_echolink
In my case, doing so help reveal to me that I had an invalid password.
Occasionally, the after reboot, the simpleusb module would fail. Still working through that; but it seems that restarting the asterisk service does the trick.
bash $ sudo systemctl restart asterisk.service
Somewhat related: I noticed that a firewall was enabled out of the box; but without "echolink" service added; the symptom being my echolink node was registered; but could not receive incoming calls. The following command added the echolink service to the firewall.
bash $ sudo firewall-cmd --zone-allstarlink --add-service=echolink
I hope some or all of this helps. Good luck and 73
Omar Asfour