ahmedsa
For mserver.altawi.com.sa
you only have an A record pointing to 78.93.244.61
Also there appear to be no nameservers, so it does not surprise me to find that
in a web browser mserver.altawi.com.sa does not resolve - Connection refused error
Also there is no mx record for altawi.com.sa anymore, it seems it has been changed since yesterday, so incoming mail will not be directed to your mail server ie mserver.altawi.com.sa.
It appears you have setup/changed everything incorrectly (in external DNS & MX records).
The solution proposed to reconfigure the router to be a modem in bridged mode & change server mode to server & gateway, is the answer to a lot of your (internal configfuration) problems (eg open port management).
Someone claims the firewall is configured to allow open ports, well here is the port scan showing open ports & it does not agree with what you claim
Without a lot of other ports being open & forwarded to your "SME server only mode" mail server, then the mail server will not function, so you have firewall problems. Your support people are telling you lies or not doing their job.
nmap -O 78.93.244.61
Starting Nmap 6.25 (
http://nmap.org ) at 2015-11-24 03:26 AEDT
Nmap scan report for mserver.altawi.com.sa (78.93.244.61)
Host is up (0.51s latency).
Not shown: 990 closed ports
PORT STATE SERVICE
23/tcp filtered telnet
113/tcp filtered ident
135/tcp filtered msrpc
139/tcp filtered netbios-ssn
445/tcp filtered microsoft-ds
593/tcp filtered http-rpc-epmap
4444/tcp filtered krb524
6667/tcp filtered irc
6881/tcp filtered bittorrent-tracker
12345/tcp filtered netbus
I read on his website that Graeme Robinson only provides ad hoc support to clients who have an annual support contract with him, so maybe you should try someone else.
I cannot help you any more, you are wasting peoples time here.
Please engage a tech support person to sort out your problems, as it seems you clearly do not understand what you are doing.
It is waste of our time when you will not follow the advice given.
You have internal configuration problems & you have external DNS & MX record configuration problems, & you seriously lack an understanding & comprehension of these technical matters.
Talk to someone locally who understands all these things & you may get the matter resolved.
I doubt that you wil resolve it yourself.