@richtea999 If a road is flagged by HERE as having a seasonal closure any time of the year, you have to check "Disable seasonal closures" to route through it -- even if the closure is for winter only and it's currently the dead of summer. Logically, it should only apply when the road is actually seasonably closed, and you want to create a route through it for future use.
There is a good forum discussion on the confusion surrounding this Toolkit routing option avoidance:
https://forum.myrouteapp.com/topic/5608/seasonal-closures-app-versus-planner-problem
The obvious (to me) option would be to have an "Ignore Closed Roads" option for creating routes, regardless of what the immediate real-time situation is. Let me decide what's passable, and what isn't. Google will always be a better investigative solution than HERE, so let me do my own research. I've suggested this before, but for whatever reason it's been ignored by the powers that be.