imtest successful but sivtest is not :-(

[JOYDEEP]

Dear list ,

in my system sieve is not working. I check the user cyrus by imtest.
the command is "imtest -a cyrus -u cyrus  localhost -s"
-----------------------------------------------------------
TLS connection established: TLSv1 with cipher AES256-SHA (256/256 bits)
S: * OK lvps87-230-8-228.dedicated.hosteurope.de Cyrus IMAP4 v2.2.12
server ready
C: C01 CAPABILITY
S: * CAPABILITY IMAP4 IMAP4rev1 ACL QUOTA LITERAL+ MAILBOX-REFERRALS
NAMESPACE UIDPLUS ID NO_ATOMIC_RENAME UNSELECT CHILDREN MULTIAPPEND
BINARY SORT THREAD=ORDEREDSUBJECT THREAD=REFERENCES ANNOTATEMORE IDLE
AUTH=PLAIN AUTH=LOGIN SASL-IR X-NETSCAPE
S: C01 OK Completed
Please enter your password:
C: A01 AUTHENTICATE PLAIN Y3lydXMAY3lydXMAbWFoYWRldg==
S: A01 OK Success (tls protection)
Authenticated.
Security strength factor: 256
-------------------------------------------------------------------

now  " sivtest -a cyrus localhost" reports
----------------------------------------------------
S: "IMPLEMENTATION" "Cyrus timsieved v2.2.12"
S: "SASL" "PLAIN LOGIN"
S: "SIEVE" "fileinto reject envelope vacation imapflags notify
subaddress relational comparator-i;ascii-numeric regex"
S: "STARTTLS"
S: OK
Please enter your password:
C: AUTHENTICATE "PLAIN" {20+}
AGN5cnVzAG1haGFkZXY=
S: NO "Authentication Error"
Authentication failed. generic failure
Security strength factor: 0
------------------------------------------------------

where may be the problem here ?