Is there something upstairs that is blocking the way?
If there isn't I once had this happen to me. I went into build mode and moved the stairs a bit and that seemed to fix it?
November - last edited November
@Lisa7958 Please check this Bug Report to see if it matches your issue. If it does please add your 'Me Too' to the report and subscribe in order to receive updates when a fix is in place. In the meantime check the second comment on the bug report for a list of workarounds that have been found: https://answers.ea.com/t5/Bug-Reports/WORKAROUND-Open-staircase-cause-routing-failures/m-p/9716427/h...