Unibox did not send because Account Protection stopped the action first. The message was not sent to LinkedIn.
The banner reads "Blocked by Account Protection: {reason}. The send was not attempted." Common reasons include a kill switch, a No seat badge, a sender that is not Active, or a suppressed contact.
Fix the reason on Safety, Billing, the sender, or Suppressions, then Send again. Write with AI only drafts text. It does not bypass Account Protection.