Can not send e-mail: adress and server domain different

Hello forum,

I am using K-9 Mail v6.804 on a Samsung Galaxy S23 with Android 14.

Sorry, but as a new user I had to replace @ with at

Long time ago I registered an e-mail adress at arcor.de with 3 alias adresses.
This was the reason why I choosed K-9 Mail years ago.
Since a couple of years Arcor was taken over by Vodafone so the new e-mail adresses are “_at_vodafonemail.de” but the older “_at_arcor.de” still work fine.

I am using 4 different Mail accounts, all set up as IMAP-accounts.
The other three work fine, except this arcor/vodafone account.

Since maybe 4 weeks or longer I tried to send a message via this arcor account and received the error messages:

  • Messages can not be sent. Error: authentication failed
  • Authtication failed. Check your server setting
    So I checked “Settings - Send e-mails - outgoing mail server” and saw:
    Server: smtp.vodafonemail.de
    Security: SSL/TLS
    Port: 465
    Authentication: Normal Password
    Username: myname_at_vodafonemail.de
    Password: hidden
    Client-Certificate: None

Of course this will lead to an authentication error because the username had to be myname_at_arcor.de.
I can change the username and check the server settings via continue-button but I still receive the authentication error.
If I close server settings and enter them again, the username ist set to myname_at_vodafonemail.de

On my PC I can still send e-mails with this accout.
Is there any chance to get it working again?

I’d keep the user/pass combination for the transfer of email as it is and such that it works. Probably with the arcor.de user/pass combination.

In the Sending Email menu for that account, there should be a submenu for Manage Identities. Wouldn’t you put your older arcor.de identities there?

Then when composing a reply or new message, choose that identity in the From: line?