Why very short messages are rejected
A first message to someone new has to be at least 10 characters and a reply in an existing conversation at least 2, so a one-character message cannot be sent at all.
The numbers
- Starting a conversation: 10 characters minimum.
- Replying: 2 characters minimum, so "ok" and "yes" are fine.
- Maximum: 5,000 characters, either way.
Leading and trailing spaces are trimmed before the count, so ten spaces and a full stop is not a way around it.
Why the floor exists
The cheapest attack on a marketplace is one character sent to a thousand sellers to see who answers. A first message long enough to contain an actual question costs the sender something and costs an automated script a great deal more. It is a low bar on purpose: it should never be in the way of a real buyer.
Other reasons a message will not send
- One of you has blocked the other. The message reads "You can no longer contact this person." Blocking works in both directions no matter who did it.
- Too many new conversations at once. There is a cap on how many different people you can start conversations with in a short window. Replying inside conversations you already have never trips it.
- The account is suspended.
- It looked like a scam. Jinu checks outgoing messages against known scam patterns. Most of the time you get a "Before you send this" panel and can send anyway after reading it. A small number of the worst patterns, such as asking someone to read back a verification code, are refused outright with "Message not sent". Editing out the flagged part is the fix.
What to write instead
"Hi, is the dresser still available? I could collect it Saturday morning." That clears the floor, tells the seller what you want, and is the kind of message that gets answered.