Hi can anyone help we have a quicktech lathe, i hit an error that a cant clear

mot 026 z1 axis negative limit
mot 025 z1 axis negative limit
plc 079 z-1 axis (-) Hardware limit
plc 078 z-1 axis (-) Hardware limit

when i hold the overtravel button error clears lets me move and home (to machine z0) as soon as i let go error comes back.

tried restarting in different positions cleaning everything...........

any suggestions?