External Monitor didn't show correct resolution
I bought a new Samsung monitor LC27JG54QQEXXY with the spec of 2560x1440, 144HZ.
I connect with my iMac 27" Late 2013 macOS Sierra, but after connected with thunderbolt converter to HTMI, my Samsung monitor only showing maximum resolution of 1920x1080.
I tried connect with my another newer iMac with macOS Mojave, with same converter and cable, the monitor work completely fine in 2560x1440.
What is the problem?
iMac 27", macOS 10.12