generate and set new token variable if postman request fails with 401

newToken.pm

if (pm.response.code === 401) {
    pm.sendRequest({
        url: 'https://YOUR-KEYCLOAK-SERVER/realms/REALM-NAME/protocol/openid-connect/token', 
        method: 'POST', 
        header: 'Content-Type:application/x-www-form-urlencoded',
        body: {
            mode: 'urlencoded',
            urlencoded: [
                {key: "grant_type", value: "client_credentials"},
                {key: "client_id", value: "YOUR CLIENT ID"},
                {key: "client_secret", value: "YOUR CLIENT SECRET"},
                {key: "scope", value: "openid"}
            ]
        }
    }, (err, res) => {
        if (err) { 
            console.log(err); 
        } else {
            pm.collectionVariables.set('bearerToken', res.json().access_token);
        }
    });
}