ahmedsa
Something here does not make sense.
You say you cannot send using Outlook, logs suggest a message is sent, but the recipients say they do not receive a message from you at external public email accounts (gmail, yahoo, hotmail), yet you say you can send to the same external accounts using webmail & the messages are received OK.
Please try using a different well known & well behaved email client.
Can you please install or use Thunderbird email client & send emails to exactly the same email addresses that you say do not receive messages, ie at gmail, at hotmail & at yahoo etc.
Configure Thunderbird with the identical SME mail server user details & email client settings as you have in Outlook 2007.
I wonder which webmail system you are really using to test sending is OK ?
Maybe you are connecting to another mail server system so please make sure you test using the mserver mail server webmail.
Please enable webmail on your SME mail server in server manager (ie on mserver.altawi.com.sa), then retest sending using the SME mail servers webmail program, login to
https://mserver.altawi.com.sa/webmailwith the same user account & password you have configured in the Outlook 2007 that you say cannot send emails.
Let us know the results (concisely & accurately) of all tests requested above.
Log file excerpts would be good where appropriate to prove your claims & assertions.
Note you use the words cannot send, but it appears you mean the recipient does not receive, which are different things technically.