Hello - the lack of an upshift (https://www.yourmechanic.com/question/car-won-t-shift-into-second-and-has-transmission-fluid-leaking-transmission-is-a-200r4-by-genesis-p) from 1st to 2nd could be dirty, burned fluid or clogged filter, or a failed Shift Solenoid "A". Low fluid level and low electrical system voltage can also make the transmission misbehave...
