asterisk18 is running.
However, asteirsk11 does not operate. Start-up will be.

When you dial from the soft phone, immediately Asterisk is killed.
Disconnected from Asterisk server
Asterisk cleanly ending (0).
Executing last minute cleanups

If Do you have you are using a Asterisk11?

Model    Buffalo WZR-HP-G300NH
Firmware Version    OpenWrt Chaos Calmer 15.05.1 / LuCI 15.05-149-g0d8bbd2 Release (git-15.363.78009-956be55)