501 error Unexpected response from SMTP server during FROM address

[Sevo]

I am having this error when I am running diagnostics on my email. The server is not seeing emails.

This is the exact error

"Warning: 501 Unexpected response from SMTP server during handshake in [path]\includes\class_mail.php on line 586"

I found this thread https://vborg.vbsupport.ru/showthread.php?t=182310

Here is his fix

I wrote an app in c# that caught the error.

There was an extra Mailto: in front of the sender name of the email. I found it in the code of the Site Name / URL / Contact Details. the line that matches up with the "Contact us Link" form field.

Thanks everyone, a lesson learned. That error number means that the send name is not in the proper or acceptable format for the mail server to read. It can connect but not send because the From name format is not known.

my question is where do I find the php files that contains the sitename/url/contact so I can look at the code?

Thanks for the help

[Dave]

The error you are receiving is different than the one in the thread you linked though.

Things I can think of which cause this: your email server does not support SSL/TLS or PHP on your server doesn't support SSL/TLS.
Check if the openssl extension is enabled in PHP.

[snakes1100]

That is the exact same error as in the link he provided.

Do you have any emails setup in your admincp for example "webmaster email" contactus email etc?
Verify they are properly set

Do you have any hacks installed that relate to emailing members?
If so disable it & retest.

[Dave]

Originally Posted by snakes1100

That is the exact same error as in the link he provided.

Do you have any emails setup in your admincp for example "webmaster email" contactus email etc?
Verify they are properly set

Do you have any hacks installed that relate to emailing members?
If so disable it & retest.

He receives the error:
Warning: 501 Unexpected response from SMTP server during handshake in[path]\includes\class_mail.php on line 586

The guy in the other thread receives the error:
Warning: 501 unexpected response from SMTP server during FROM address transmission in

501 is just a global error code.

In case you send less than 10k emails every month and you can't seem to solve this, try using mailgun.com. It's free up to 10k emails/month and very fast.

[Sevo]

Originally Posted by Dave

The error you are receiving is different than the one in the thread you linked though.

Things I can think of which cause this: your email server does not support SSL/TLS or PHP on your server doesn't support SSL/TLS.
Check if the openssl extension is enabled in PHP.

Hi Dave,

I had my server guy check the server and all is good to go on the server. Do you have any other suggestions?

THanks