The connection could not be made critical

Ambiguous by nature, and worth reading with the sending address in mind. A receiver that is simply down refuses everyone; a receiver blocking our address refuses only us, and the pattern across addresses on the same node is what distinguishes them — one address failing where others succeed is a block, not an outage. A failure here also triggers the five-minute offline period (connection_offlinetime), so one refusal quietly suppresses attempts to that server for the next few minutes and those show up as untried rather than refused.