Thank you for that insight. I will try your solution.EX4 is a 5g wifi drone.
Samsung S5 has WiFi 802.11 ac. (It is a fact as I just googled for it and it is confirmed.)
So theoretically they should work well together.
It that does not work, it could be the app as a culprit.
If you were using Enjoy Fly app and it failed to connect, suggest that you try C-Fly app.
Nice to hear it is sorted.Found a solution for my situation at least. I am able to connect to the drone with the app after a factory reset of an old samsung J7 Start phone. Connected first time and appears stable. Using C-Fly app. Next, will see if it will fly.
Again, thanks for your response.