Why arabic letters appears as "?" symols !

1. 1- Open your webmail from
http://yourdomainname.com/webmail, then enter your email
and password.

2. 2. Click on Horde mail.

3. 3- Click "Login" button.

4. 4- From the left side menu choose "Options".

5. 5- Then from the list under "Options" choose "Mail".

6. 6- Click on "Message Composition".

7. 7- Select from " Your default charset for sending messages "
dropdown menu >> " Unicode (UTF-8) ", Then click Save options
button .