Telegram Messenger is a cloud-based instant messaging and voice over IP service. You can easily install it on your smartphone (Android and iPhone) or computer (PC, Mac, and Linux). It is free and without any ads. Telegram allows you to create bots that you can interact with.
There are numerous examples but everything starts with a bot and your telegram account. As this is "web-based", you can only go so fast on a free account. My guess is the service is:
- Overloaded because it is free,
- Under sized because it is free,
- Limited/throttled to prevent overload.
The example that uses a bot to send email is even more encumbered with delays.