Freedrum is working with Android devices, but it is not the same amount as iOS. This is to do with Google & Apple taking different paths when it comes to bluetooth and midi over bluetooth. We are unfortunately not in control of this.
Right now though Android is behind we have seen Freedrum working great on S8 and a few other Android devices beautifully.
The Galaxy S6 and any iteration of it looks to not be compatible in any way at all. From emails, social media and now on the forum we have tried and failed to get them to connect a number of times. The thing with Android at this point is not even just a certain model, but who it is being sold from. For example in the US you will have one version of the S6 and in Europe you will have another.
This looks like we will have to pull it from compatibility list. We apologize for all the confusion and issues you have had.
Please email us if you do not have another device so we can assist you with a return of your kit.