UAVtoolbox is a great app, however it doesn’t yet work with the H3. I too have the H3 and contacted the developer of UAVtoolbox. They haven’t been able to update it for the H3 since Yuneec hasn’t sent them one.
However, before I was experiencing binding issues, I was about to work with the developer to assist in getting the information they need to make it comparable with the H3. I am still in limbo, however, why don’t you contact them and find out.