error session

[cecov74]

Hi, when I try to start npm run start I receive this error

file:///var/www/vhosts/xxxxxxx/wa.xxxxx.it/whatsapp-gateway/server/session/Session.js:23
    return sessions ?? null;
                     ^

SyntaxError: Unexpected token '?'
    at Loader.moduleStrategy (internal/modules/esm/translators.js:133:18)

why?