%d expands to empty string ========================== The problem is that your username string lost the domain part. Dovecot doesn't keep track of the domain separately from username, so if something changes username from "user@domain" to just plain "user", the domain is lost and %d returns nothing. If you have 'auth_debug=yes', this shows up in logs like: ---%<------------------------------------------------------------------------- Info: auth(user@domain.org): username changed user@domain.org -> user ---%<------------------------------------------------------------------------- Below are some of the most common reasons for this. Settings -------- 'auth_username_format = %Ln' lowercases the username but also drops the domain. Use 'auth_username_format = %Lu' instead. 'auth_username_format' changes the username permanently, currently it's not possible to make it affect only the authentication part. SQL --- 'password_query' gets often misconfigured to drop the domain if username and domain are stored separately. For example: ---%<------------------------------------------------------------------------- # BROKEN: password_query = SELECT username AS user, password FROM users WHERE username = '%n' AND domain = '%d' ---%<------------------------------------------------------------------------- The "username AS user" changes the username permanently and the domain is dropped. You can instead use: ---%<------------------------------------------------------------------------- # MySQL: password_query = SELECT concat(username, '@', domain) AS user, password FROM users WHERE username = '%n' AND domain = '%d' ---%<------------------------------------------------------------------------- Or you can return username and domain fields separately and Dovecot will merge them into a single user field: ---%<------------------------------------------------------------------------- password_query = SELECT username, domain, password FROM users WHERE username = '%n' AND domain = '%d' ---%<------------------------------------------------------------------------- (This file was created from the wiki on 2011-11-16 14:09)