Joint following error all axis

Hi all,
I've been running a 3 axis stepper cnc voor a couple of years now. Everything was working fine 4 days ago. Today after powering on when I try to jog or G28 I get joint following errors on all axis. If I lower the feedrate substantially I can jog manually, bur starting any job fails joint 'x' following error. I havent made any changes to hall or ini file. Can anyone point me in the right direction for troubleshooting?
Thanks in advance.

Does LinuxCNC complain about latency when starting?

No, no other errors. Only joint following error.

What PC?
What interface, parallel port or Mesa or Pico systems or...?
What drives? Step/dir or analog or EtherCAT?
What do you expect G28 to do? It is not homing as in 3D printers.
Upload the hal and ini files here so we can have a look.

The pc is a HP Z400; workstation (quad core xeon with 8 gb memory and ssd). The interface is parallel port with step/dir. G28 moves all axis to machine zero.
I will upload the hal and ini files tomorrow (it's night time overhere). But I don't think that's the problem because it was working perfectly for the last couple of years.

Today all is functioning normally again. Ran a 30 minutes program without errors. So I don't know what happened yesterday, maybe I need a new pc.

Z400 are very good, so i would not change it, but in case you have issues again, try removing memory modules, never happened to me on a Z400, but happens sometimes on Z420 and happens a lot on Z600, at boot reports of memory issues that mostly disappear on their own.

Okay, will try that when problems retturn. Thanks!

You are welcomed, always.