When IPv6 is enabled on namespace, the static route for the ip6-dp creates the following error..
setsockopt(SO_BINDTODEVICE): No such device
From what I understand, accel is trying to set the static route in the default namespace and the interface is missing.
I tried to fix it.. it seems that is working for quite a time now.
https://github.com/accel-ppp/accel-ppp/compare/master...vang1804:master