I have a very simple RPI3 / SainSmart 8 channel SSR setup. I have GPIO18 set as out and wired to the relay board. I can turn on the relay (at least its LED lights appropriately).

My issue is that it will not trigger the garage door opener. I have the relay wired straight through to the COM / PB terminals on the opener.

If I short both these terminals with a screwdriver the door opens as expected...

The opener is a Wayne Dalton Pro-Drive 3222C-Z.

What am I missing?