Question about StarTech DisplayPort to HDMI - 4K

Hi, I have a question regarding the Refresh rate of the display. So this is my display: https://www.galaxus.ch/en/s1/product/aoc-q27g2ebk-2560-x-1440-pixels-27-monitor-22705817?supplier=406802 . It supports 155 Hz and I don't know if it makes a difference or not, but I have it connected as my second display monitor. I connected the video adapted via Display Port > HDMI but it seems like I only have a 60 Hz refresh rate.. In the description they say that it works up to 155 Hz so I'm not sure if I'm doing something wrong or what. Thank you