Why is my host attach failing with error message A0029 Access denied to specified controller?

When you run the attach host script, your hosts are not attaching and you get a error message similar to the following example.

Nov 07 18:19:56 tl2vdu ibm-host-attach.sh[5562]: + echo '{"incidentID":"a11babcd-202d-4c97-111a-1111abdcdf11","code":"A0029","description":"Access denied to specified controller.","type":"Authentication"}'
Nov 07 18:19:56 tl2vdu ibm-host-attach.sh[5562]: {"incidentID":"f97fabec-602d-4c97-946a-8699ccdcdf75","code":"A0029","description":"Access denied to specified controller.","type":"Authentication"}
Nov 07 18:19:56 tl2vdu ibm-host-attach.sh[5562]: + echo 401
Nov 07 18:19:56 tl2vdu ibm-host-attach.sh[5562]: 401
Nov 07 18:19:56 tl2vdu ibm-host-attach.sh[5562]: + [[ 401 -ne 201 ]]
Nov 07 18:19:56 tl2vdu ibm-host-attach.sh[5562]: + echo 'Error [HTTP status: 401]'
Nov 07 18:19:56 tl2vdu ibm-host-attach.sh[5562]: Error [HTTP status: 401]
Nov 07 18:19:56 tl2vdu ibm-host-attach.sh[5562]: + exit 1
Nov 07 18:19:56 tl2vdu systemd[1]: ibm-host-attach.service: Main process exited, code=exited, status=1/FAILURE
Nov 07 18:19:56 tl2vdu systemd[1]: ibm-host-attach.service: Failed with result 'exit-code'.

Your host attach script is older than one year and the HOST_QUEUE_TOKEN value expired.

Download a new copy of your host attach script or ignition file from your location.

When your host attach script expires, your unassigned hosts enter a Unresponsive status. For more information, see Why do my unassigned hosts have an Unresponsive status?