botframework-sdk: BotBuilder doesn't work with Microsoft Teams for newly-created bots

The following code just listens for incoming messages and replies with Hello to them. It fails when a message is received from Microsoft Teams when handled by a recently created bot, but works perfectly if I do the same with bots, that were created a month ago.

const fs = require('fs');
const restify = require('restify');
const builder = require('botbuilder');

const server = restify.createServer({
  key: fs.readFileSync('../privkey.pem'),
  certificate: fs.readFileSync('../cert.pem')
});
server.listen(8889, function () {
  console.log('%s listening to %s', server.name, server.url);
});

const connector = new builder.ChatConnector({
  appId: '... Bot ID ...',
  appPassword: '... Bot Password ...'
});
const bot = new builder.UniversalBot(connector);
server.post('/incoming', connector.listen());

bot.dialog('/', function (session) {
    session.send('Hello');
});

For the recently created bots it stops on the following error:

Error: Request to 'https://smba.trafficmanager.net/v3/conversations/19%3A7bccb3fd-ec20-4d39-934d-14be2002c27e_423f5dfe-6118-4a00-ba23-4fafc4b6fc19%40unq.gbl.spaces/activities/1483459651513' failed: [404] Not Found
    at Request._callback (/raid/www/sapho.drud.cz/bot/node_modules/botbuilder/lib/bots/ChatConnector.js:415:46)
    at Request.self.callback (/raid/www/sapho.drud.cz/bot/node_modules/request/request.js:186:22)
    at emitTwo (events.js:106:13)
    at Request.emit (events.js:191:7)
    at Request.<anonymous> (/raid/www/sapho.drud.cz/bot/node_modules/request/request.js:1081:10)
    at emitOne (events.js:96:13)
    at Request.emit (events.js:188:7)
    at IncomingMessage.<anonymous> (/raid/www/sapho.drud.cz/bot/node_modules/request/request.js:1001:12)
    at IncomingMessage.g (events.js:292:16)
    at emitNone (events.js:91:20)

See the detailed log here: https://gist.github.com/drudv/24f82af359f6d8d9313033cfe9c6f947 Also here is a log for the “old” bots, for which it works as expected: https://gist.github.com/drudv/aaf838e1ed2c47d568a0858f748a7b30

I have 5 different bots (2 were registered today, others were created a month ago) and can confirm that it’s reproducible only with these two recently created bots. All of them have correct Messaging endpoint on https://dev.botframework.com/bots page (test connection returns Accepted) and Microsoft Teams channel is enabled for them.

A few more observations:

1. Old and new bots are handled by different servers. It’s evident from the User-Agent header of incoming requests, which is BF-Skype (Microsoft-BotFramework/3.1 +https://botframework.com/ua) for the old bots and Microsoft-SkypeBotApi (Microsoft-BotFramework/3.0) for the recently created bots.

2. If a message is sent from the test chat window on https://dev.botframework.com/bots then this code works for all bots. So the issue relates only to Microsoft Teams channel.