A nice track, but it feels a bit too upbeat and happy for ambient music. The synth bass in particular doesn't seem like it sits with the rest of the mix too well. Perhaps a more mellow bass might have been a better option.
I think some pads in the background or drone tones might also help - the main instrument choice helped out a little bit, but I think more mellow instruments like pads (especially using them with drawn out drone tones) could've helped a bit more. Subtle touches and uses of certain percussion instruments, such as the triangle, could help as well. Hope this helps.