I have Nextcloud 20.0.6 and the latest mail app from the app stroe. I have a mail account at the german hoster IONOS by 1und1.
This combination wored good in the past. But for the last two months or so I cannot send mails anymore. I get the error “Error: Request failed with status code 500”. All of my investigations don’t solve the problem.
I reinstalled the app and add my account in different variations. The initial setup worked and I receive mails. But when it comes to send a mail it doesn’t work.
I use dietpi as operating system and installed nextcloud over the dietpi-software installer. The only logfile I found was under /mnt/dietpi_user/nextcloud/ and the file is empty.