2 line keys on phones but second caller gets a busy signal

[k.parrent]

I cannot seem to figure out how to allow both of my line keys to ring on incoming calls. When I have taken a call on line 1 and then a call is presented to line 2 the caller hears a busy signal. I would like for line 2 to ring and then a 3rd call to be forwarded to voice mail. Can someone tell me what I'm missing?

[sarond]

What system type?

[k.parrent]

Mitel 470 release 6. Staging it in my office atm.

[zoo]

Try - terminal -> Multi lines -> select 3 (default 1), permission set -> busy on busy -> untick...
BR

[k.parrent]

Thanks zoo. You nailed it.