Importing data from firebase to bigquery

I'm trying to import data from firebase to big query upon onWrite event and getting same error each time function is triggered given below.

PartialFailureError: A failure occurred during this request. at /user_code/node_modules/@google-cloud/bigquery/src/table.js:1086:13 at Object.handleResp (/user_code/node_modules/@google-cloud/bigquery/node_modules/@google-cloud/common/src/util.js:134:3) at /user_code/node_modules/@google-cloud/bigquery/node_modules/@google-cloud/common/src/util.js:465:12 at Request.onResponse [as _callback] (/user_code/node_modules/@google-cloud/bigquery/node_modules/retry-request/index.js:120:7) at Request.self.callback (/user_code/node_modules/@google-cloud/bigquery/node_modules/request/request.js:188:22) at emitTwo (events.js:106:13) at Request.emit (events.js:191:7) at Request. (/user_code/node_modules/@google-cloud/bigquery/node_modules/request/request.js:1171:10) at emitOne (events.js:96:13) at Request.emit (events.js:188:7)

my function code is

exports.addtobigquery = functions.database.ref('/mn_users').onWrite(event => 
{
  const dataset = bigquery.dataset(functions.config().bigquery.datasetname);
  const table = dataset.table(functions.config().bigquery.tablename);

  return table.insert({
    id: event.data.key,
    name: event.data.val().name,
    email: event.data.val().email
  });

});

I want to figure out what I'm doing wrong?