I created a bot with the python-telegram-bot library and the user has the ability to navigate through the states, but when there is a bug, I need to restart the bot and when I restart the bot, the user needs to type /start again in order to communicate with the bot, instead of this, is there a method that I can let the user to continue from whichever state the user was in the bot before?
The states of ConversationHandler are stored in memory by default, that's true. If you want these states to be persisted across reboots of your python script, please have a look at PTBs built-in persistency setup.
Disclaimer: I'm currently the maintainer of python-telegram-bot.