Deliverability
Soft Bounce
A temporary delivery failure — the inbox is full, the server is down, or the message is too large.
Soft bounces are temporary. The receiving server has agreed the address exists but cannot accept the message right now. Most ESPs automatically retry soft-bouncing addresses several times before marking them as a hard bounce. Common causes: full mailbox, server down, message exceeds size limits, or content blocked by an inline filter.