Why did the Heroku bot stop responding to commands?

Question

git

Friends, hello! There was such a problem: a bot uploaded to Heroku a little less than a month ago stopped responding to commands. At the same time, in the application on the Heroku website, the bot has an enabled status (I attach a photo).
Made an attempt to delete the current application and create a new one. After the command (heroku ps scale: worker=1) in git, the bot responds to the requested commands and goes back to sleep.
What could be the problem? It is worth noting that the bot worked on a free plan, but the number of requests per month was definitely not exceeded.