My Galaxy S6 Dual Sim (920FD) isn't getting LTE on AT&T

I have properly signed up for the wireless service on AT&T and I'm seeing 4G, H, or H+ on top of my device instead of LTE. I checked with AT&T and they said that my plan shows that I should be on LTE. I'm in Chicago downtown, so the coverage is not an issue..

I've also checked the LTE frequency and it does consist of band (2,4,5,17). What could be the issue?