Tunnel offline - 100% packet loss

AndyRH

A friend and I have a WG tunnel between 2 pfSense FWs. It has worked well for over a year. A few days ago, it went off-line. Neither of us touched WG.
When I do a packet capture, I can see the FWs pinging each other on the correct port, but the GW stays off-line.
We have both restarted the WG service.
We have both went through the settings to verify nothing was changed.
Both sides are running 24.03

What could go wrong? Where do I look?

09:09:44.216872 IP 75.A.B.C.842 > 172.D.E.F.842: UDP, length 148
09:09:44.252887 IP 172.D.E.F.842 > 75.A.B.C.842: UDP, length 148
09:09:44.254045 IP 75.A.B.C.842 > 172.D.E.F.842: UDP, length 92
09:09:49.363877 IP 75.A.B.C.842 > 172.D.E.F.842: UDP, length 148
09:09:49.445027 IP 172.D.E.F.842 > 75.A.B.C.842: UDP, length 148
09:09:49.446205 IP 75.A.B.C.842 > 172.D.E.F.842: UDP, length 92
09:09:54.578324 IP 172.D.E.F.842 > 75.A.B.C.842: UDP, length 148
09:09:54.579509 IP 75.A.B.C.842 > 172.D.E.F.842: UDP, length 92
09:09:59.698243 IP 172.D.E.F.842 > 75.A.B.C.842: UDP, length 148
09:09:59.699428 IP 75.A.B.C.842 > 172.D.E.F.842: UDP, length 92
09:10:04.755018 IP 172.D.E.F.842 > 75.A.B.C.842: UDP, length 148
09:10:04.756200 IP 75.A.B.C.842 > 172.D.E.F.842: UDP, length 92
09:10:09.888127 IP 172.D.E.F.842 > 75.A.B.C.842: UDP, length 148
09:10:09.889309 IP 75.A.B.C.842 > 172.D.E.F.842: UDP, length 92
09:10:15.012695 IP 172.D.E.F.842 > 75.A.B.C.842: UDP, length 148
09:10:15.013907 IP 75.A.B.C.842 > 172.D.E.F.842: UDP, length 92