Loading screen + mongodb timeout

[ecawthon]

Symptom: chat.cloyne.org shows the three loading dots and the correct page title (CloyneChat) as set by rocketchat, but never loads.

In /srv/log/rocketchat/current:

=> awaited here:                                                                                                        
    at Promise.await (/Rocket.Chat/bundle/programs/server/npm/node_modules/meteor/promise/node_modules/meteor-promise/promise_server.js:60:12)
    at SynchronousCursor._nextObject (packages/mongo/mongo_driver.js:1091:12)
    at SynchronousCursor.forEach (packages/mongo/mongo_driver.js:1105:22)
    at Cursor.(anonymous function) [as forEach] (packages/mongo/mongo_driver.js:887:44)
    at OplogObserveDriver._runQuery (packages/mongo/oplog_observe_driver.js:729:16)
    at packages/mongo/oplog_observe_driver.js:699:14
    at Meteor.EnvironmentVariable.EVp.withValue (packages/meteor.js:1304:12)
    at packages/meteor.js:620:25
    at runWithEnvironment (packages/meteor.js:1356:24)

repeated many times. Final entry after checking in browser and before force restarting:

 => awaited here:
    at Promise.await (/Rocket.Chat/bundle/programs/server/npm/node_modules/meteor/promise/node_modules/meteor-promise/promise_server.js:60:12)
    at SynchronousCursor._nextObject (packages/mongo/mongo_driver.js:1091:12)
    at SynchronousCursor.forEach (packages/mongo/mongo_driver.js:1105:22)
    at SynchronousCursor.map (packages/mongo/mongo_driver.js:1115:10)
    at SynchronousCursor.fetch (packages/mongo/mongo_driver.js:1139:17)
    at Cursor.(anonymous function) [as fetch] (packages/mongo/mongo_driver.js:887:44)
    at Object.<anonymous> (packages/matb33_collection-hooks.js:445:81)
    at Object.collection.(anonymous function) [as update] (packages/matb33_collection-hooks.js:146:21) 
    at Collection.update (packages/mongo/collection.js:585:31)                       
    at Collection.Mongo.Collection.(anonymous function) [as update] (packages/dispatch_run-as-user.js:325:19)
    at BaseDb.update (app/models/server/models/_BaseDb.js:229:25)
    at Collection.model.update (app/models/server/models/_BaseDb.js:110:16)
    at AccountsServer._expireTokens (packages/accounts-base/accounts_server.js:1018:16)
    at accounts.expireTokenInterval.Meteor.setInterval (packages/accounts-base/accounts_server.js:1432:14)
    at Meteor.EnvironmentVariable.EVp.withValue (packages/meteor.js:1304:12)
    at packages/meteor.js:620:25
    at runWithEnvironment (packages/meteor.js:1356:24)
  name: 'MongoNetworkError',
  errorLabels: [ 'TransientTransactionError' ],
  [Symbol(mongoErrorContextSymbol)]: {} }
Exception in setInterval callback: SwitchedToQuery{}

Fixed (temporarily?) by restarting mongo container and then re-running rocketchat from within the rocketchat container. Not sure what actually caused this or if it will happen again.