Issue Spam filtering disabled on mailbox, messages still go to spam folder

[Xav2c]

Hi,

I'm using plesk 12.5 running on a 14.04 ubuntu server, the install IMAP/POP3 is dovecot, and using roundcube as webmail.
On one particular mail account, almost all emails go into the spam folder, around 60%, and even if i disable the antispam filter, messages keep falling in the spambox.

What can i try to understand why messages are still falling in the spambox?

 

[Xav2c]

Sorry to bump it, but i really need help here

 

[Xav2c]

Ok so i think i got it...
I traced back the mails in the logs, and they go to INBOX folder, not spam.
So that's where it struck me that the Thunderbird IMAP client was probably responsible for the issue... and moving the mails in the spam folder (how could i have missed that?)
I'll check tomorrow but in the meatime, sorry for the useless post.