Question Gmail's 'via' doesn't match the domain of the email address

[Mathijs]

Okay so first of all thank you for reading this!
I've had great help the last time I posted so I thought I'd give it another go.

Within Plesk I have multiple domains with all at least one email address. One of those domains is a Wordpress website with a Contact Form 7 form on the frontend. When someone fills in the form my client gets the feedback sent to his info address via Gmail.

For some reason that I can't seem to figure out, Gmail shows my main domain as the 'via'. I have searched everywhere and tried a bunch of stuff but no luck. I really thought I found it when I got to Tools & Settings -> Mail Server Settings and noticed the 'Outgoing mail mode' was set to 'Send from the specified IP addresses'. But sadly changing this to 'Send from domain IP addresses' did not fix it.

All my current websites are on the same IP addresses, so maybe I need to change that? If so I wouldn't know what's the wise thing to do. I also have the feeling that shouldn't be the fix.

Hope anyone on here can help. Thanks in advance!

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[MarkM]

Are you using an email account on your main domain to authenticate your messages?

 

[Mathijs]

Are you using an email account on your main domain to authenticate your messages?

Hi Mark,

First of all thanks for responding. I'm not quite sure what you mean by 'to authenticate your messages'. I have one email address configured on the main domain, but I'm not sure how that authentication would work.

 

[MarkM]

By authentication I mean like SMTP auth. Are you specifying an SMTP server or just using the wp_mail() function?

 

[Mathijs]

By authentication I mean like SMTP auth. Are you specifying an SMTP server or just using the wp_mail() function?

I haven't configured anything regarding Email inside of Wordpress so I'm assuming I use the wp_mail() function.
I just did some additional Googling and found this article below regarding setting up SMTP auth. Should this do the trick?

How to Use SMTP Server to Send WordPress Emails

 

[MarkM]

Yea, it should clear it up.

Is the via domain your server's hostname by chance?

 

[Mathijs]

Yea, it should clear it up.

Is the via domain your server's hostname by chance?

Hi Mark,

First of all apologies for the late response. I've been crazy busy and eventually got a friend to help me with this issue.
I ended up using the plugin Post SMTP and got it to work. Minus a few messages when running a Connectivity Test. Hoping someone on here can shine some light on this:

PS: I'm using a different domain to test this, but it is setup in the exact same way.

 

[MarkM]

As far as the screenshot, It's the SMTP banner that's being sent;

[root@pink ~]# telnet yamahaguitars.nl 25
Trying 136.144.133.85...
Connected to yamahaguitars.nl.
Escape character is '^]'.
220 mathijslemmers.com ESMTP Postfix

 

[Mathijs]

I see.. And would I be able to change this inside of Plesk or Wordpress?
Doing some searching on Google gives me this article, but I'm hoping for an easier solution.

That is if it's even something to bother with at all?

How to change Postfix SMTP banner?

 

[MarkM]

I wouldn't worry about it - you'll just be moving a warning like that to another domain. I'm not sure exactly how that plugin works, but if you insert the server IP instead of the domain it may not display the warning.... just an idea.

It's set by the server's hostname when Postfix is installed, so modifying that file is the only way I am aware of that you can change it.