FTP troubles with Roundcube vacation plugin

[Frank Bonnet]

Hello

I'm in trouble with vacation plugin which perform an FTP session at 
localhost , for an obscure PAM/FreeBSD reason the FTP session is not 
always working ...

The machine runs FreeBSD 7.2-R with Dovecot 1.2.10 imap server

Any clarification welcome !
Thank you.

Sometimes it works well

connection from localhost (127.0.0.1)
Feb 16 13:21:10 mail ftpd[46479]: FTP LOGIN FROM localhost as bonj
Feb 16 13:21:10 mail ftpd[46480]: FTP LOGIN FROM localhost as bonj
Feb 16 13:21:29 mail ftpd[46541]: connection from localhost (127.0.0.1)
Feb 16 13:21:29 mail ftpd[46541]: FTP LOGIN FROM localhost as bonj
Feb 16 13:21:29 mail ftpd[46542]: connection from localhost (127.0.0.1)


then suddenly it stops working

Feb 16 13:23:19 mail ftpd[46782]: connection from localhost (127.0.0.1)
Feb 16 13:23:19 mail ftpd[46782]: pam_acct_mgmt: new authentication 
token required
Feb 16 13:23:19 mail ftpd[46782]: FTP LOGIN FAILED FROM localhost
Feb 16 13:35:55 mail ftpd[48202]: connection from localhost (127.0.0.1)
Feb 16 13:35:55 mail ftpd[48202]: pam_acct_mgmt: new authentication 
token required
Feb 16 13:35:55 mail ftpd[48202]: FTP LOGIN FAILED FROM localhost
Feb 16 13:35:55 mail ftpd[48203]: connection from localhost (127.0.0.1)
Feb 16 13:35:55 mail ftpd[48203]: pam_acct_mgmt: new authentication 
token required