Humm there should be a prompt with the error message. Doesnt it show to you? Which android version are you in?
nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z No UI shows after tapping the zap button if a device does not have a lightning wallet already. There should be a prompt to let the user know that they need a lightning wallet.
Discussion
Android 13 Galaxy S22
So, I am reading in a few places that Toast Messages (the thing we use to notify errors) can be disabled on Samsungs if the app's notification is also disabled. Can you check if this brings them back to you?