Outbound routes with linksys spa 3102

Hello,

I have 2 trunks with linksys spa 3102, the trunks are set with max channels = 1.

I have this problem: if the first 3102 in the list of outbound routes is down (if is has no network connection or if is power off) then the call doesn’t use the second trunk, it hangup the call.

How can I solve this issue?

thanks in advance