Suddenly KMail can not send e-mails: "Remote host closed the connection".

English Applications
#1

I am working with OpenSUSE for 15 years now, and I solved lots of problems. This one is puzzling me, however. Suddenly, in KMail, I cannot send mails anymore: “The remote host closed the connection”. I did not change anything in the settings. The problem is the same on all six of my computers here in my house. But it is not the provider’s fault (Proximus, formerly Skynet) because in their webmail application I can send e-mails without any problem. It all began yesterday 17th April: I sent two messages which did NOT reach their destination, and since then every time I try to send, I get the same message: “Message could not be sent. The remote host closed the connection”. Restarting my Bbox-3 router did not help. I played with the KMail settings, without any effect. The settings are: SMTP-server = relay.skynet.be – no authentification required – no encryption – port 25 – “LOGIN”. Changing any of these does not help one bit: relay.proximus.be , or setting the authentification, or an encryption, changing the port to 465 or 587, or “LOGIN” to “PLAIN” : nothing works. I don’t suspect a recent update to be the culprit, because this also happens on my other PC’s that were not yet updated when I tried them. Receiving e-mails works flawlessly, and Akregator is working fine too. What is happening? Thanks to everybody who can help me out …

#2

Perhaps your IP address has been blacklisted for some reason? You could contact your email provider about that.

#3

Review their support page to start with.

#4

I found connections set up by kmail to be unstable for some reason. There is an easy fix. Set up an email server: https://karlmistelberger.wordpress.com/2017/12/26/e-mail-auf-dem-opensuse-desktop/

#5

I have no idea why you have started this in the Dutch languiage section. Luckily it seems that many English language people are nevertheless trying to help you

But I will move this to the English language section to give it a better exposure (and to keep the Dutch section as such).

#6

I did that, and I’m not blacklisted. That’s why I can send mail through their webmail, in by Chromium browser.

#7

The settings are: SMTP-server = relay.skynet.be – no authentification required – no encryption – port 25 – “LOGIN”. Changing any of these does not help one bit: relay.proximus.be , or setting the authentification, or an encryption, changing the port to 465 or 587, or “LOGIN” to “PLAIN” : nothing works.

The page I linked to earlier mentions…

Server for incoming e-mail:

  • Address:
    imap.proximus.be> - Port:
    993> - Security:
    SSL>
   	 **Server for outgoing e-mail:**
  • address:
    relay.proximus.be> - Port:
    587> - Security:
    STARTTLS, TLS or SSL>
 	For both the incoming and outgoing server, you must enter your complete e-mail address and the password of your mailbox.
#8

I spoke with their technician for half an hour on the phone, he doesn’t see any provider problems, and through their webmail I can send without problems. Seems to be something from my side.

#9

Do you have another mail client or mobile device (eg smart phone) available to test the account with?

#10

Also, try

telnet relay.proximus.be 587

You should get something like

~> telnet relay.proximus.be 587
Trying 195.238.20.30...
Connected to relay.proximus.be.
Escape character is '^]'.
220-smtp.skynet.be ESMTP
220 Belgacom relay service - authentication required!
#11

I have no IMAP but POP. Settings: pop.skynet.be , no encryption, port 110 . I’m afraid changing to IMAP will damage the other users in my home, and anyway it works fine as it is since long years. Just the sending is suddenly problematic, and just through KMail.

#12

What I get is “command not found” …

#13

Yes, as I said I use Proximus webmail in my Chromium browser and that works fine. It’s just KMail that, suddenly, doesn’t send.

#14

Don’t change the incoming settings. Just the outgoing (SMTP) settings.

Try the telnet command I gave you.

#15

Yes, but for webmail you’re interacting with the server directly. I mean another device with email client to test SMTP connectivity.

#16

Then install telnet.

#17

Outgoing settings are now as you suggested: relay.proximus.be WITH my authentification: mail address and password STARTTLS port 587 “LOGIN”
As for telnet , it just gives “command not found” – maybe I should install telnet ?

#18

Yes, as I just posted. :slight_smile:

#19

I did telnet, and to my surprise I got this:
Trying 195.238.20.30…
Connected to relay.proximus.be.
Escape character is ‘^]’.
554-smtp.skynet.be
554 Access denied- Under investigation for spam abuse- Please visit for more info https://www.proximus.com/en/ipremoval/form
Connection closed by foreign host.

I cannot imagine why that is, but now I see the problem is with Proximus, not with KMail. So I will visit their site now again … KMail is innocent !

Thanks a lopt for helping me out !

#20

There you go! Glad to have been of guidance. BTW, as your ISP probably assigns a dynamic public IP address, you’re likely to have been caught up as an innocent bystander.