Hi,
I show that the Audio Box iTwo has 2 Mic/Int (1/4”) inputs with Preamps so as long as your acoustic has a built in preamp, with a good battery, it should be fine.
Just be sure to adjust the PreAmp gain on the Audiobox so you are putting out a good signal
Also as someone else mentioned, make sure you have the input selected for the Studio One and the Output routed to the L/R as well as in your song set routing your inputs & outputs correctly.
John