==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.2.1
- Deployed with iRedMail Easy or the downloadable installer?
- Linux/BSD distribution name and version: Debian 10 Buster
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro?
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Hello, everyone.
After I ran apt-update && apt-upgrade the /etc/sogo/sogo.conf was overwritten. I restored it from the sogo.conf.dpkg-old and could access my mails and contacts again via ActivSync. Now I have the problem that I can not send any email. Via the web interface of SOGo www.mydomain.com/SOGo I can log in and if I want to send email I get the error "Request failed!
The same on my other clients like mobile phone or PC.

I can receive emails but I cannot send emails.

Here the log output:

May 20 13:25:02 sogod [1576]: [WARN] <0x0x5654645cbab0[SOGoUserDefaults]> expected an NSString for 'SOGoMailComposeFontSize' (ignored)
2020-05-20 13:25:02.536 sogod[1576:1576] EXCEPTION: <NSException: 0x565463ee7080> NAME:NSInvalidArgumentException REASON:NGSmtpClient(class) does not recognize clientWithURL: INFO:(null)
May 20 13:25:02 sogod [1576]: 84.153.99.185 "POST /SOGo/so/contact@mydomain.com/Mail/0/folderDrafts/newDraft1589973878-1/send HTTP/1.0" 501 0/1306 0.085 - - 92K