故障

malfunction / breakdown / defect / shortcoming / fault / failure / impediment / error / bug (in software)

happening / instance / reason / cause / intentional / former / old / friend / therefore / hence / (of people) to die, dead

to block / to hinder / to obstruct

single point of failure

technical breakdown / malfunction

to troubleshoot / to check components individually for problems / troubleshooting

fault resolution / trouble clearing