Just to clear something up the 4 of these devices are new, using an old device which had it's serial made back in 2021 (with the same prefix works) perfectly
Also the serials are being generated, I can confirm this by disconnecting the internet, playing on a local server
On the server log each user has a unique serial
I think the issue is new serial generated by mta-server64 linux, are being rejected by the mta service.