iPhone IMAP sent folder

Dear all,

i've recently changed hosting provider (aruba.it) for my own website (and emails). So far I've used GMail to manage my email which I check on the iPhone and using Thunderbird on my PC and Mac.

Since I've moved to the new provider I've created a new email IMAP account on my iPhone with the following entries given me by the hosting company:

Incoming Mail Server

Host Name: imaps.aruba.it

User Name: my email address

Password: *******

Outgoing Mail Server

Host Name: smtps.aruba.it

User Name: my email address

Password: *******

Use SSL: ON

Authentication: Password

Server Port: 465

On the Advanced Tab:

Mailbox Behaviors:

Drafts Mailbox: On the Server -> Drafts

Sent Mailbox: On the Server -> Sent

Deleted Mailbox: On the Server -> Trash

Deleted Messages:

Remove: After one week

Incoming Settings

Use SSL: On

Authentication: Password

IMAP Path Prefix INBOX

Server Port 993

When I write an email on thunderbird or webmail I can find this email in my sent folder on all devices (webmail, iPhone, Thunderbird) but when I send an email using my iPhone there is no trace on neither sent folder (nor iPhone, nor webmail, nor Thunderbird) although the email gets send and the receiver gets its email.

Since I need that all sent emails are stored in my sent folder I'm wondering if anyone has got an idea on how to solve this issue. I've checked the folder names on webmail, thunderbird and my iPhone and they are identical.

I've got also another problem which I think it may be related to this issue. I've got an email on Thunderbird marked as unread which I can't find when scrolling through my iPhone since they should be ordered by date. I thought that the problem was only on the SENT folder but I've realized that there was an email missing; all other are in sync. When I used to look for this specific email using SEARCH INBOX function I could find it. Does anyone had the same problem and knows a possible solution?