iMessage and Facetime are not impacted by the proxy.
Unfortunately, I'm not sure what the deal is with iMessage on Mavericks at the moment. Apple's official system requirements page now lists OS X 10.11 (El Capitan) as the minimum requirement. However, iMessage and Facetime are still working for me on Mavericks despite that.
If you figure it out, please share!!
Yes I have restarted many times.Have you restarted?
This came as a surprise. With the proxy off, I remember sending a test message to myself in the iOS 15 Messages: the message didn't come in in the Mavericks iMessage. When I enabled it, the messages started flowing in and out both ways. Are you sure they don't use the proxy?
It seems that both of you two are able to use iMessage and FaceTime without any issues. Were you signed in to them before they changed the requirement? I just fresh installed Mavericks in Mid July, because my computer was having some issues. Maybe it's that if you were already signed in before the change, you can still use it. But new people can no longer sign in. So if someone was logged in right now, and they were to log out, they would not be able to log in anymore. That's my theory. Do you guys have any other signed out Mavericks machines to test it on? I don't know if it's an issue with my router or ISP. My Wi-Fi uses WPA3 security, which is slightly newer.