How to fix Deployment replicas not ready, pods failing health checks in Kubernetes

kubectl describe deployment -n <namespace> <name>
kubectl get pods -n <namespace> -o wide
kubectl logs -n <namespace> <pod-name>

kubectl edit deployment -n <namespace> <name>

# Increase readiness probe delay:
readinessProbe:
  httpGet:
    path: /health
    port: 8080
  initialDelaySeconds: 60  # Increased

# Check environment variables:
kubectl describe pod -n <namespace> <pod-name>

# Check application logs:
kubectl logs -n <namespace> <pod-name> --previous

kubectl edit deployment -n <namespace> <name>

# Increase resources:
resources:
  requests:
    memory: "256Mi"
    cpu: "250m"
  limits:
    memory: "512Mi"
    cpu: "500m"

kubectl get deployment -n <namespace> <name>
# READY should show N/N