Cannot read property 'id' of null

Cannot read property 'id' of null

          
              TypeError: Cannot read property 'id' of null
    at forumController.single (C:\inetpub\wwwroot-iranbinary\app\http\controllers\forum\forumController.js:78:86)
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)