Is this an unlocked international Note 5, since I see 4G and not LTE. On AT&T 4G (is LTE) and HSDPA+ (is H+). Stop into your local AT&T store and check the APN settings associated with a Note 5 specifically and make the changes accordingly. The key thing is you did take your microSIM out of your current phone which is already provisioned for LTE and your account also is provisioned.
I found this out the hard way with my ZenFone 2 that is International and I needed to take a SIM out of a phone provisioned for LTE and do the APN settings to get full LTE speeds.