No synth sound in midiguitar2 iOS

I am using a Melo Audio TS Mini interface for my guitar into iPhone 14 via a USB to lightning Apple Camera adaptor. The TS mini shows up in the app input and output sections and the correct channel is selected. I can see levels in the gain meter on the midi guitar app and signal coming through. With the direct monitoring button engaged on the TS mini the guitar direct sound comes through but no synth instruments. I tried several of them. Tried adjusting the Mix , gain etc. Visually signals are coming through and audio output for the dry guitar but no synths. When the direct monitoring button is off on the TS mini no sound comes through my monitors at all. Any help would be appreciated.