Email Server not connecting to SMTP server


I have recently faced some problems with setting up an email-Adress for my nextcloud to use (the one in Administration --> basic settings):

When I put all my information down, as described on the Email-Providers Website:

Send Mode: SMTP      Encryption:SSL/TLS
From adress: webmaster @ [mydomain]
Authentication method: Login      Authentication required
Server adress:   :   587
credentials: webmaster@[mydomain]      [password]

(Ihave double checked the password and tried a different provider ( and also changed the settings to other options, but allways got this errror message, when trying to send a test eMail:

A problem occurred while sending the email. Please revise your settings. (Error: Connection could not be established with host :stream_socket_client(): php_network_getaddresses: getaddrinfo failed: Name or service not known)

I can however reach that server from the same network with Thunderbird on my PC.
I also ran


from my lxcs’ console and got an answer with 0 % package loss and a ~20ms ping so nextcloud should be able to reach the server.


I have some mailboxes at the same provider, and at least for me the connection details you posted are incorrect. The port should be 465, then it works.


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I tried both ports before, as they are both given on the Strato website and just tried the 465 again, but get the same error, are your other configurations the same?

Did you search the forum? I found this thread (sadly enough it’s german)

Maybe it is of any help for you?

Interestingly the other thread claims it’s not working - whereas for me it works flawlessly:



Well I see it that way: if you have problems connecting your strato-account it could be because of THAT.
I’M not sure that it would be valid for all strato-users, though.

naja, eine echte Lösung abseits davon einen eigenen Mailserver aufzusetzten (was ich bei Zeiten eh noch machen will, aber erstmal die Strato-Mail als Übergang nutzen wollte) wird da leider nicht geboten, soweit ich das sehen kann, aber trotzdem danke ich habe den Post tatsächlich noch nicht gefunden gehabt.
Scheint aber wohl ein generelles Problem mit Strato zu sein. (auch wenn mein nächster kommentar dagegen spricht)

Update: I recently checked my spam folder on the receiving e-Mail address and what do I find? Right a mail from my Nextcloud-Server informing me that my setup was successful, sadly I am not able to replicate that result anymore and do not know which settings were used to archive that as I played around with them quite a bit during that time.
I can not recall any setting that did not throw up the aforementioned error-message thought which means that I either missed an Instance where this message was not present, or Nextcloud was able to send an email nevertheless.

Aaarg, I know that feeling… :slight_smile: I hope you figured it out again in the meantime. My settings from above still work with STRATO for me.

I know this is an old thread but someone should stumble upon it at some point. I kept getting the same errors on my installation of Nextcloud on a docker container. After a few days of digging and testing, I was able to get an email through after dropping the “SMTP” from the domain name and changing to Port 25, with STARTTLS (due to no SSL on nexthub container). Also had to drop the authentication. worked on my installation, might on yours depending on the server configuration.