Problem accessing management VLAN over SSTP

I have a central location and a few remote locations with more than one router. These are in a management VLAN 200
ppp1.PNG
I can remotely access 10.1.2.1 and 10.1.3.1 from the central location
I can ping 10.1.2.3 from 10.1.2.1

I can’t connect to 10.1.2.3 from 10.1.1.1 and I need to to administer them remotely.

This is the PPP on the central router
admin.jpg
I think the problem is with the route,
IPremote.PNG
route.PNG
But I don’t know what do do to fix it. Any ideas or links for further study?