If this is an issue for you, please feel free to open a new thread instead of reviving older ones. Many reasons could explain servers not showing up, ranging from “you’re logged into a different user than the owner of the server” to “using an irregular mount location.”
Since the explanations (and solutions) vary so widely, it’d help to have more information about what servers exist:
ls -la /var/games/minecraft/servers/
as well as whether the listed owners there match the user being logged into the webui.