Reverse DNS does not match SMTP Banner [duplicate]

I'm new to this site but I have found many good answers on this site before. I have also searched for my actual question but I didn't found the answer or at least I didn't understand what should I do for that.

The topics I have already read:

Reverse DNS does not match SMTP Banner
SMTP Reverse DNS Mismatch Reverse DNS does not match SMTP Banner
https://stackoverflow.com/questions/31542300/reverse-dns-does-not-match-smtp-banner

And many more I found on google.

Problem :

We have a dedicated server with 16 IP addresses, we use 4 IP addresses actually, 1 is main IP, 2 for NS's and 1 for mail server.

So in our DNS config file we have :

lynxis-sa.eu. 86400 IN NS ns01.lynxis-sa.eu.  
lynxis-sa.eu. 86400 IN NS ns02.lynxis-sa.eu.

ns01.lynxis-sa.eu. 14400 IN A IP2  
ns02.lynxis-sa.eu. 14400 IN A IP3

ptr00.lynxis-sa.eu. 14400 IN A IP1  
ptr01.lynxis-sa.eu. 14400 IN A IP2  
ptr02.lynxis-sa.eu. 14400 IN A IP3  
ptr03.lynxis-sa.eu. 14400 IN A IP4  

lynxis-sa.eu. IN A IP1

localhost.lynxis-sa.eu. IN A 127.0.0.1

lynxis-sa.eu. IN MX 0 smtp.lynxis-sa.eu.  
lynxis-sa.eu. IN MX 10 mail.lynxis-sa.eu.

smtp.lynxis-sa.eu. 14400 IN A IP1 (For ssl)  
mail.lynxis-sa.eu. 14400 IN A IP4

Hostname : s1.lynxis-sa.eu

The Reverse for each IP is correctly set on IP manager as same you can see here.

I manage a VPS with exactly same configuration but with one IP and everything is ok. But on this server, with every MX Lookup on http://mxtoolbox.com, I get the warning message "Reverse DNS does not match SMTP Banner".

For info: we use Centos 6 and Centos Web panel.

Thank you for your help in advance :)

For other people who may have same problem, the answer is :
Postfix SMTP banner show multiple hostnames

Solution 1:

The answer is also given at mxtoolbox, please check it.

What does the Warning – Reverse DNS does not match SMTP Banner mean? – SMTP Diagnostic Tool

The short answer is that the reverse IP address name is not contained in the server HELO or EHLO banner. In the example below, the string “someotherdomain.com” is not found anywhere in the server banner, which is reporting “example.com“. This is only a warning, and in some cases you may have no control over this. However, if you have the ability to make these match, you should. Some mail servers look for this and use it to mark messages you send as questionable. Most mail systems will not reject your messages outright, but this may effect your spam score increasing the likelihood your messages will be marked as spam.

In other words, it is a best-practice you should endeavor to follow. It doesn’t mean you are a bad person or won’t be able to send email.

220 mx.example.com StrongMail SMTP Service at Wed, 09 Sep 2009 17:00:01 -0700

Not an open relay.
0 seconds – Good on Connection time
0.156 seconds – Good on Transaction time
OK – 1.2.3.4 resolves to mail.someotherdomain.com