Locked my Mac Pro from my iPhone, but the code to unlock it won't work

I am trying to unlock my 2017 Mac Pro with a recent upgrade to the Monterrey OS (was running Big Sur until a few weeks ago).

I was leaving town for a while, so I thought as a safety measure, I would lock my desktop computer using Find My Phone's lost device lock. Once I locked it, I got nervous about it not unlocking (had that happen before), so I immediately tried to unlock it.

The code I used to lock it now would not unlock it. I logged into cloud to unlock it from there. All that did was tell me the unlock code I already know. Apparently my Mac Pro is not connecting to the Apple servers because I tried to play a sound to it and it still says pending.

It has been online over WiFi, but just in case, I ran a hardwire to it. I logged into my router to make sure I see it. It has an IP address, but if I try to use that IP address to access the Mac over the intranet, nothing. Not even a login screen.

What am I doing wrong here? How can I unlock my Mac Pro?

Thank you in advance.