[Dovecot] error pop email

[indra wardhana]

i got error when downloading the email using pop. the message is "The 
RETR command did not succeed. Error retrieving a message. Mail server 
responded: ity: 3 (Normal)

server dovecot-1.0.10 (debian etch-backports package)
client mozilla thunderbird-1.5.0 (debian etch package)
any advice ?

tq