Bluetooth amplifier pairing problem

[Pexy13]

Greetings!
I ordered a 3w bluetooth amplifier from ebay for a little project but i can't connect my phone (LG V30)to it.
It can see it but but it doesn't want to connect to it. When I tried the same thing with my dads iphone 7 it connected and worked perfectly.
What is the cause of this and how can I fix it?
This is the amplifier moddule: https://www.ebay.com/itm/3W-2-Bluetooth-Audio-Receiver-Mini-Digital-Amplifier-Board-Module-Micro-USB-I8H4/163597127953?hash=item2617261111:g:BKQAAOSwjXZciNVs&enc=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&checksum=163597127953257dd0626b6c4c2baa51c2a4d5588a33
Thanks!