sudden joint 0 1 2 error, homing all wrong etc..

Ok...  LinuxCNC has been driving me crazy...

I'm new to LinuxCNC  and only got to use it as a "new to me" CNC Mill (3 Axis G0704 Clone) followed me home a few weeks ago.
the Machine came with a super dated computer - and I replaced it..
got LinuxCNC up and running (with a few exceptions: can't get probe_basic to install) but was actually starting to mill parts with Gcode made in fusion360...

I wanted to fine tune the stepper configuration and loaded the one I had working...  
all went well...  and I saved it as a NEW CONFIGURATION (kept the original)

BUT ever since: IN ANY CONFIG:
I get  errors "Joint 1 on limitswitch error" "joint 2 on limitswitch error", "joint 0 on limitswitch error".

the only way I can get the machine to move is if I enable "Override limit" in the AXIS GUI.
And there's more weird: when I try to HOME the machine - it does it in the WRONG DIRECTION  and completely IGNORES the Limit Switches and "crashes" the machine...

Again, this has been running before .. and I'm using the "unmodified" config from before... 
rebooting, etc... all to no avail.

help is really welcome...
thanks

Thanks.  But I think I’ve figured it out.  
the culprit was a damaged induction sensor 

it was slightly awkwardly mounted and when i tried to do the stepconfig the machine essentially crashed into it and damaged it.

after i disconnected it the problem was gone at least on the two axis with working ref switches
i have a replacement delivered by Monday luckily 

replacing it is unfortunately a bit more work as the table needs to come off…
but that I’m ok with 

at least now I’ve learned what causes the behaviour and I’ll be changing the switch location…