If you're watering every morning the soil surface is perhaps damp most of the time (it certainly is possible that a container would need frequent watering but watering is better done as needed rather than as a daily routine so make sure you actually do need to water, check the media first - you can do that by pushing your index finger down into it to see if it feels damp).
Added to that the planter appears to be in shade which would also encourage moss. Is it in shade all day?
From the picture, and unless you've added plants, it looks like you have mostly perennials in the planter?
Edit: crossed-posted with Hetty, sorry Hetty!
