I recently unlocked a Claro Puerto Rico M4 Aqua and inserted an Orange España SIM. I previously used the same SIM in a Motorola MotoG 4G and the data was functioning at 4G. With my unlocked M4 it reach only H+. What the problem could be?
Bands may be different, do you know by chance the model number? Go in settings, about phone and check the model number, it will be something like E2306.
LTE band 1(2100), 3(1800), 8(900), 20(800) are not supported by US version of M4 Aqua (E2306) so if your carrier uses them then you are not going to get 4G network. Same is the case with me in India
