What are “alias rejections”?

Alias rejections involve indirect address failures:

What email aliases are:

Alternative addresses pointing to real mailbox. info@ forwarding to support team. Old addresses redirecting to new ones. Role addresses mapping to individuals.

Alias rejection scenarios:

Alias removed: Redirect no longer exists. Alias disabled: Temporarily turned off. Target mailbox gone: Alias points to deleted account. Misconfiguration: Alias setup error.

Bounce characteristics:

May say "user unknown" even though alias was valid before. Target mailbox may exist but alias broken. May not indicate alias was involved.

Handling:

Treat as hard bounce if consistent. May be worth retry if intermittent. Difficult to distinguish from regular invalid address.

Alias rejections are broken forwarding rules. The shortcut no longer leads anywhere.