With the exception of the 'Play With The Computer' section all the 'BOT' accounts are operated by people other than Lichess . The only people who can answer your question directly are those who operate the maia accounts. Hopefully your contact can give you info n it.
I'd imagine that the bot was either overloaded when you tried to rechallenge, or they have some kind of rate limiting feature to stop the same user from monopolizing usage of the bot.
I'd imagine that the bot was either overloaded when you tried to rechallenge, or they have some kind of rate limiting feature to stop the same user from monopolizing usage of the bot.