Honor band 6 with iphone 6s plus

I have an honor band 6 (which i connect to an iphone 6s plus) .. for 3 months, it was perfect for the job, but a week ago, when i press on the "reject the call" sign on the screen, the call is rejected on the band but not on the iphone nor on the caller's side ..I tried restarting and resetting the band but nothing changed .. The Honor support suggested I try another phone, and it worked well with my brothers phone .. So, the issue happened in the phone itself!

Can somebody help?