External account pop3 does not work after upgrade

[sirio81]

After upgrading from zimbra 5.0.16 to 6.0.10 user with pop3 external account get message

system failure: Unable to connect to IMAP server: DataSource: { id=d742ebcf-f087-4e0a-83fe-1825ee0dba3c, type=imap, isEnabled=true, name=username, host=mail.local, port=143, connectionType=cleartext, username=username, folderId=100497 }, LOGIN failed

If I try to insert a password and test user I get

Connection reset

I also set

zmprov mcf zimbraImapCleartextLoginEnabled TRUE
zmprov mcf zimbraPop3CleartextLoginEnabled TRUE

I noticed that if I enable ssl flag...it works.

Do you have any idea of what happened.
On a large installation it would be a stress to set the flag to all external users.

Thank you.

[hafiz]

do you get this issue resolved ? I'm getting the same problem and run out ideas what going on.

[sirio81]

Hi, unfortunatly I do not remember if I fixed the problem and how. I'm sorry.