We have Windows Server 2008 R2 with RRAS. Windows clients connect just fine. Tried to add a new l2tp-ou1 interface, setting up: IP, username, password, IPSec secret. Everything else is default (tried different Mikrotik devices, with default config, stable and long-term). Doesn't work. There are messages "NO-PROPOSAL-CHOSEN" and "failed to bind to :: Bad file descriptor" - both are vague.
What else can we try? Please help.