Few days ago I installed the custom sender email-adress noreply@reissner-ernst.de. I tested it and it works. But now the sender is again a jotform dom

Few days ago I installed the custom sender email-adress noreply@reissner-ernst.de. I tested it and it works. But now the sender is again a jotform domain.

I see that you have already changed the sender email back to noreply@reissner-ernst.de. Please allow me to inform you that the sender email usually reverts back to the jotform domain (noreply@jotform.com) when there is an issue with the details of the custom SMTP sender. Can you please contact your email service provider and make sure that the SMTP details are correct and up to date? 

If the issue still persists, please let us know.
Thank you.

The problem is: I can't check the data which I used to set up the custom sender adress because your setting form does not show the used settings. So I can't control it .

Anyway I want to install an other sender adress: noreply@jures-fachseminare.de
But do I need this anymore once I'll have installed acustom domain via CNAME.
See my questions in thread

1478251435

If you need to edit your SMTP settings, here is how: https://www.jotform.com/help/241-How-to-Edit-Delete-Sender-Emails-on-SMTP-Settings