Delivery Temporarily Suspended Unknown Mail Transport Error Postfix Upd May 2026

Dovecot changed the location of its binary or the protocol for LMTP sockets. For example, dovecot-lda (Local Delivery Agent) may have moved from /usr/lib/dovecot/deliver to /usr/libexec/dovecot/dovecot-lda .

This article provides a deep dive into the root causes of this error, specifically focusing on scenarios that arise . We will explore why this happens, how to diagnose the exact issue, and step-by-step solutions to restore normal mail flow. Understanding the Error: What Does It Mean? In Postfix terminology, a transport is the method by which a message is delivered to its final destination. This could be a local mailbox (e.g., using local transport), an LMTP socket, a Dovecot deliver agent, or a relay host (e.g., smtp transport). Dovecot changed the location of its binary or

The update relabeled binaries or changed file contexts. Postfix may no longer have permission to execute a transport binary. We will explore why this happens, how to

dovecot unix - n n - - pipe To (add v flag and increase verbosity): This could be a local mailbox (e