Cellular Calls from Macs Failing

I noticed recently that I can't make or accept calls from my Macs to my SE running 11.1 (was also happening on 11.0.3 earlier this week, but I updated-I should go to 11.1.1 ASAP).

I have had the issue on three Macs: 2013 Air, 2010 Pro (both 10.10.5), and 2014 mini (10.12.6).

All are signed in to iCloud and FaceTime. I DO see the call attempt under Recents on my iPhone, and hitting the Info button shows the call was canceled.

This is happening on my home network (AirPort Time Capsule Wi-Fi) and I've tried at work, where I was actually successful making a test call from my work computer on 10.11, but not my Air. (I will experiment more with this tomorrow, but I believe my work Mac was on Ethernet at the time, not Wi-Fi.)

Annoyingly, calls ring through on my home Macs, but accepting them drops the call.

My only major clue so far is the following line from Console, once the calls fail:

2017-11-12 11:22:23.723 AM configd[51]: no interface for external service id

Steps I have currently taken:

Hard restarted and normally shut down iPhone

Restarted all Macs

Signed in and out of iCloud and FaceTime on all devices

Turned off two factor (since it's properly built in to 10.12 I thought it may be the culprit)

Changed DNS settings back to automatic at home

Changed to my ISP provided Wi-Fi

Modified Service Order in System preferences on Mac to place Wi-Fi at the top

Changed Time Capsule from bridge mode to DHCP and NAT

Restored original hosts file

Flushed DNS cache

The terminal steps from here, which return

sudo mv /etc/sysctl.conf ~/Desktop/sysctl.conf.old
mv: rename /etc/sysctl.conf to /Users/Jonathan/Desktop/sysctl.conf.old: No such file or directory

on the final line.
Anyone have any insight on this? I'll test tomorrow at work as well.