Mail not sending

Good day everyone.

I have a question about the Mail feature in my Nextcloud AIO Docker setup. I have an email sent to a group of 106 recipients, but now it is stuck in Outbox giving an error every time I try to send it. It seems that my Raspberry Pi 4 can’t handle the Nextclooud instance, as the load on CPU max out. (But that’s an issue for another time) My questions are: Each time it tries to resend, does it resend to everyone? I don’t see anything in the sent items, but I am receiving a few error mails and a few automatic replies, so it is sending, but does the error mean it’s not sending to everyone or did it send to everyone? I hope you guys understand my broken English. Please help!

EDIT: There are no errors related to mail in the logs under the Administration menu. In my mail server, nothing shows up in the Sent messages either. I must add, I always get an error when sending a mail, but after resending it for the first time, then it sends, but I don’t want to send the mails over and over again and every time it does send.

I do receive emails correctly.



Nextcloud does not have a mail server, only a mail client. So it will transfer the message to whatever mail server you have configured, and that server will figure out ho to distribute it to the 106 recipients. On the IMAP client side, it’s just one message.

It’s unclear from your description whether it might be a client or server issue. What SMTP error code are you getting?

Ok, I might have all my terms wrong, but to explain it different than before, the mail client (Nextcloud) it is stuck in Outbox, saying: “Message could not be sent”, but although it isn’t on the server side’s Sent items, it does seem like it’s sent, because I am getting replies, but I want to know what the process is for Nextcloud to send the message, does it send the message 106 times or just one time to the server? Last listed would mean the server sent it to all 106 recipients, and Nextcloud only sent one, right? But then why isn’t it in the sent items on my server (SOHO client for Mailcow server)? And why is it stuck in Nextcloud’s mail client’s Outbox?

Thank you for replying. I hope my question is clearer now? I can’t see any SMTP errors in Nextcloud’s logs in administration menu.


Hi, you should possibly open an issue about this here: Issues · nextcloud/mail · GitHub

You need to create the default folder first - Drafts - Trash , or change the default folder configuration in the mail setting

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Had the same problem, GiClouds answer fixed it for me… :slight_smile: