@677,439
4chan has a shitty spam filter that gets randomly triggered (based on threat score, board, image attachment, by chance, etc.) which leads to “IP range blocked”, even if you're not actually violating any rules. This allegedly happens more often for Firefox users. Some assume this is a marketing ploy to push people into buying a 4chan pass.
Check out this PHP imageboard source code for more info:
https://raw.githubusercontent.com/zearp/4chan/refs/heads/main/imgboard.php