Persistent Lua/script checksums do not match

[mpzambee]

• What are the specs of the server?

I have an i7-7800x @ 4.7 GHz, 16GB of RAM,  and a Samsung 960 Evo SSD

• What OS is the server running on?

Windows 7

• What is your connection speed? speedtest.net

39Mbps down, 5.3Mbps up

• Did you try to fix your problem and how?

Yes. We have tried completely uninstalling the game, deleting the c:\users\you\zomboid folder, restarting steam, restarting computers, forwarding ports on both sides, disabling firewalls/av software, absolutely everything.

• What's the issue, exactly and what did you try to fix it?

The issue is that, even with perfectly fresh installs of Project Zomboid (from Steam), we cannot play together in coop. We can get through character creation, and then when "It was the end of times" shows up, we get disconnected. It doesn't matter who is hosting and who is joining, we always get a lua checksum mismatch. This is particularly confusing since we are both literally using fresh installs of the game, which pass Steam's verification. The dedicated server has the exact same problem.

• Is the server being run on a VPS or home computer?

Home computer, all ports forwarded, and have tested it with the computer plugged directly into the modem.

 

This is a really, really frustrating problem, as we have spent roughly 20 hours over the last week trying absolutely everything we can think of to fix this, everything we can think of, and none of it is working. We have previously- months ago- and it worked perfectly fine without anything other than port forwarding, but now we're completely unable to play together.

[mpzambee]

Again, we're getting checksum errors with perfectly fresh installations of Project Zomboid from Steam, with zero mods of any sort, which makes no sense.