You are not able to include both the strict option and backup-sla-preferred-color. The strict option drops traffic immediately when the preferred-color tunnel is no longer available. The backup-sla-preferred-color {color} allows traffic to be forwarded to a secondary WAN tunnel. https://www.cisco.com/c/en/us/td/docs/routers/sdwan/configuration/policies/vedge-20-x/policies- book/application-aware-routing.html