MongoError: pool destroyed

[freezy]

View details in Rollbar: https://rollbar.com/freezy/server/items/55/

MongoError: pool destroyed
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/core/connection/pool.js", line 804, in Pool.write
            cb(new MongoError('pool destroyed'));
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/core/wireprotocol/command.js", line 107, in _command
        pool.write(message, commandOptions, commandResponseHandler);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/core/wireprotocol/command.js", line 25, in command
        _command(server, ns, cmd, options, callback);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/core/wireprotocol/query.js", line 57, in Object.query
      command(server, ns, findCmd, commandOptions, callback);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/core/topologies/server.js", line 640, in Server.query
      wireProtocol.query(this, ns, cmd, cursorState, options, callback);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/operations/find.js", line 24, in FindOperation.execute
        server.query(this.ns.toString(), this.cmd, cursorState, this.options, callback);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/operations/execute_operation.js", line 163, in topology.selectServer
          operation.execute(server, callbackWithRetry);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/core/topologies/server.js", line 828, in Server.selectServer
      callback(null, this);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/topologies/topology_base.js", line 363, in Server.selectServer
        return this.s.coreTopology.selectServer(selector, options, callback);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/operations/execute_operation.js", line 150, in executeWithServerSelection
      topology.selectServer(serverSelectionOptions, (err, server) => {
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/operations/execute_operation.js", line 81, in executeOperation
            return executeWithServerSelection(topology, operation, handler);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/core/cursor.js", line 545, in Cursor._initializeCursor
          executeOperation(cursor.topology, cursor.operation, (err, result) => {
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/cursor.js", line 191, in Cursor._initializeCursor
        super._initializeCursor(callback);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/core/cursor.js", line 748, in nextFunction
        self._initializeCursor((err, result) => {
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/core/cursor.js", line 202, in Cursor._next
        nextFunction(this, callback);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/operations/common_functions.js", line 235, in nextObject
      cursor._next((err, doc) => {
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/operations/next.js", line 26, in NextOperation.execute
        nextObject(cursor, callback);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/operations/execute_operation.js", line 83, in executeOperation
            return operation.execute(handler);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/cursor.js", line 217, in Cursor.next
        return executeOperation(this.topology, nextOperation, callback);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/operations/find_one.js", line 26, in FindOneOperation.execute
        cursor.next((err, item) => {
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/operations/execute_operation.js", line 83, in executeOperation
            return operation.execute(handler);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/collection.js", line 1026, in Collection.<anonymous>
        return executeOperation(this.s.topology, findOneOperation, callback);
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/node_modules/mongodb/lib/utils.js", line 639, in Collection.deprecated [as findOne]
        return fn.apply(this, arguments);
  File "NativeCollection.(anonymous function) [as findOne] (/var/www/server/production/v2.3.8/node_modules/mongoose/lib/drivers/node-mongodb-native/collection.js", line 166, in <unknown>
  File "/var/www/server/production/v2.3.8/node_modules/mquery/lib/collection/node.js", line 42, in NodeCollection.findOne
      this.collection.findOne(match, options, cb);
  File "/var/www/server/production/v2.3.8/node_modules/mquery/lib/mquery.js", line 2024, in model.Query.Query.findOne
      this._collection.findOne(conds, options, utils.tick(callback));
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/lib/query.js", line 2110, in model.Query.<anonymous>
      Query.base.findOne.call(this, {}, (err, doc) => {
  File "/var/www/server/production/v2.3.8/node_modules/mongoose/lib/helpers/query/wrapThunk.js", line 16, in model.Query._wrappedThunk [as _findOne]
        fn.call(this, cb);
  File "/var/www/server/production/v2.3.8/node_modules/kareem/index.js", line 369, in process.nextTick
          process.nextTick(() => fn.apply(this, arguments));
  File "internal/process/next_tick.js", line 132, in _combinedTickCallback
  File "internal/process/next_tick.js", line 181, in process._tickCallback