Cant change password via roundcube

==== Required information ====
- iRedMail version: 0.8.6
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): PGSQL
- Linux/BSD distribution name and version: Devian 7
- Related log if you're reporting an issue:

Apr  4 07:28:29 bushveld roundcube: DB Error: [7] ERROR:  syntax error at or near "$1"#012LINE 1: ...dbname=\'vmail\'', E'UPDATE mailbox SET password='$1$/IqlBAE...#012                                                             ^ (SQL Query: SELECT * from dblink_exec(E'host=\'127.0.0.1\' user=\'roundcube\' password=\'Vr5rpKU0SLVsJa4MvGggRU0yzxuvlH\' dbname=\'vmail\'', E'UPDATE mailbox SET password='$1$/IqlBAEI$xzfA2S.XgyzqyAnRANVXe0',passwordlastchange=NOW() WHERE username='postmaster@*******'')) in /usr/share/apache2/roundcubemail-0.9.2/program/lib/Roundcube/rcube_db.php on line 416 (POST /mail/?_task=settings&_action=plugin.password-save?_task=&_action=)

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Hi

please see error log, for some reason user passwords cant be changed via roundcube, can you assist?