Hmm, could well be a flagged IP, but there's no way of knowing really.
There is a useful thread written by an ex-developer which I usually share with people struggling with bans: https://osbot.org/forum/topic/124429-preventing-rs-botting-bans-v3/ta
I'd say the key take away point is to keep a low profile. Keep sessions short (personally I like 30 minutes, although it depends on what I am botting), use generous breaks, and play legitimately between sessions. Also, be sure not to bot on an account you are very invested in.
Hopefully that helps, although keep in mind that bans are random and unpredictable - at no point are you ever safe!
Good luck
Apa