Since two days, my netcologne-smtp configuration no longer works. It used to work with STARTTLS on port 587 with smtp.netcologne.de using my user account. I have verified my credentials, configured Thunderbird with the exact same settings and am able to send mails via Thunderbird.
I failed to find ANY configuration that works with multiple providers (Google,Netcologne, Telekom) and finally created an isolated account with Google, allowed less secure apps to access the account and only then I was able to get my printer to send scans again.
When I use the original configuration, I get error 017-715 (which I have not found anywhere, only 017-714). When I access my embedded web server on the printer, I get the warning from my browser that it's certificate would be not trusted. My assumption is that the certificate of the SMTP server needs to be existent in the printer's certificate store OR that the printer needs to have an CA certified certificate (and not a self-signed certificate). However, I have no idea how to do try either of these possibilities and maybe my assumption is completely wrong. Please advise on how to get a regular configuration going without having to lower my security in the mail account at Google.