Scrollbar not working when press up/down key

[pxhoang1992]

i set max-height and overflow-auto in react-autosuggest-list and scrollbar not working when i press up/down key. this is my code?

.react-autosuggest__suggestions-container {
display: none;
}
.react-autosuggest__suggestions-container--open {
display: block;
}
.react-autosuggest__suggestions-list {
max-height: 400px;
overflow-y: auto;
position: absolute;
top: ${props => props.top}px;
width: 500px;
list-style: none;
margin-top: 0;
margin-right: 10px;
padding-left: 0;
object-fit: contain;
box-shadow: 0px 5px 14.7px 1.3px rgba(0, 0, 0, 0.17);
background-color: #ffffff;
}

when i try change set max-height and overflow-y: auto on .react-autosuggest__suggestions-container--open but scrollbar disappear.
this is my code:

.react-autosuggest__suggestions-container {
display: none;
}
.react-autosuggest__suggestions-container--open {
display: block;
overflow-y: auto;
max-height: 400px;
}
.react-autosuggest__suggestions-list {
position: absolute;
top: ${props => props.top}px;
width: 500px;
list-style: none;
margin-top: 0;
margin-right: 10px;
padding-left: 0;
object-fit: contain;
box-shadow: 0px 5px 14.7px 1.3px rgba(0, 0, 0, 0.17);
background-color: #ffffff;
}

please help me?
Thank,
Hoang