So I tested earphones with 5 other Samsung smartphones and they all work except on J4+.....
Earphones are MOB MO9347 and by their manual they support:
• Stereo Earbuds
• Bluetooth Version 4.2
• Support Profile: HFP 1.6, HSP 1.2, A2DP
1.3, AVCTP 1.4, AVDTP 1.3 and AVRCP 1.5
My J4+ doesnt even see them when scanning for BT devices.... Is there any ideas what, how, why? Have all updates on phone. Tried every 3rd party BT app in store. Reset device to factory, absolutely everything I could think off. If I am reading well it should work by BT support specifications on phone and earphones, but still it doesn't. I am missing something, it is not supported?
So after a lot of search, there is a model of J4+ with only BT 4.0 support and I think that is reason why it doesn't work -.-
Even if you Google, you will not easily find that info.