What if you use these settings for the arcor account:

imap.arcor.de on 993, SSL/TLS, normal password, User Name = email address; outgoing mail.arcor.de on 587, STARTTLS, normal password, User Name = email address.

https://maildienste.de/arcor/

Thanks, but tried before and tried again. Does not work.

What is your antivirus? They (such as AVG/Avast) are known to block secure connections to mail servers. If it's not Windows Security, try running Windows in safe mode to test for startup app interference.

Shouldn't be the cause since no problem with imap.web.de. Also no poblem before updating to Thunderbird 115.01.

Re: sfhowes Top 25 Contributor 7/28/23, 10:51 AM

I did what you recommended but didn't get an immediate success. However, today (new day, new luck) I can send and receive emails in Thunderbird.

The problem remains that emails sent from Thunderbird are not shown neither in Thunderbird ("Gesendet" = "sent") nor in the Vodafone app.

Check Account Settings, Copies & Folders, to see where sent messages are stored. Depending on the mail provider, sent mail might be stored in a folder named Sent, Sent Items, Sent Mail etc. Right-click the account in the Folder Pane, Subscribe, Refresh, and see which folder contains corresponds to mail sent in the Vodafone app, then subscribe that folder in TB, and select it in Copies & Folders. It might take a few tests to establish a common sent folder between TB, other mail apps, and the folders defined by the provider.

Regarding your last recommendation it seems to me that this is alright in my settings. However, today I noticed that the problem I encountered: "The problem remains that emails sent from Thunderbird are not shown neither in Thunderbird ("Gesendet" = "sent") nor in the Vodafone app." does not happen if I use a specific alias name! (To be clear the problem did not happen before I installed Thunderbird 115.01.) Specifically, this alias name is the name of my account when I got it some years ago: "name"@nexgo.de. "nexgo" was a brandname of arcor. Some years after vodafone bought arcor the account was changed into "name"@arcor.de which is also the account setting in Thunderbird. To repeat: If I use "name"@nexgo.de as sender there is no problem. Thunderbird shows the message (in German): "The message is being copied into the sent folder". If I use the account name or any other alias this does not happen and the email does not show up in the sent folder.

I forgot to mention that the emails are really sent and received by the addressee.

Re: sfhowes Top 25 Contributor 7/28/23, 10:51 AM I did what you recommended but didn't get an immediate success. However, today (new day, new luck) I can send and receive emails in Thunderbird. The problem remains that emails sent from Thunderbird are not shown neither in Thunderbird ("Gesendet" = "sent") nor in the Vodafone app.

The picture shows that the Sent folder is a subfolder of the IMAP Inbox, which is probably why there's no consistency between sent messages in TB and other devices. I think you should look at the folder structure in webmail, where I expect the Sent, or similarly named folder, is a subfolder of the account, at the same level as Inbox, Trash etc. If that is true, you should subscribe to that folder in TB and set it as the target of sent messages in Copies & Folders.

The structure of the Vodafone account seems to have "Posteingang (inbox)" and "Gesendet (sent)" on the same level. There is also a folder called "Eigene Ordner (own folders)" that contains an item called "Sent". When I send from the Vodafone web site the sent email is listed under "Gesendet". When I send from Thunderbird the sent email is listed under "Sent" on the Vodafone web site. In Thunderbird the two folders correspond to two folders each one called "Gesendet" in the user interface. However in the file structure in /AppData/Roaming/Thunderbird/Profiles/imapMail/imap.arcor.de besides the folder INBOX.sbd there are the files INBOX, INBOX.msf and Sent.msf. The to the above corresponding files are both in the folder INBOX.sbd, namely "Gesendet" and "Sent-1". Apart from these there are also files "Gesendet.msf" and "Sent.msf" and "Sent-1.msf" and others. All this was already so before I installed Thunderbird 115.01 only that now only emails with sender "name"@nexgo.de are listed in on of the "sent" folders. When (after switching off Thunderbird) I moved in the Windows explorer the files "Gesendet" and "Gesendet.msf" from the folder INBOX.sbd to the parent folder imap.arcor.de on starting Thunderbird again the two files were moved back the INBOX.sbd folder. I also tried out to change in Account Settings, Copies & Folders in "store a copy in" "another folder" so that emails sent from Thunderbird are stored in the same folder as emails sent from vodafonemail.de, which is not bad at all. However, only for emails with sender "name"@nexgo.de!

Update: Just found out that apparently all the emails sent from any alias but "name"@nexgo.de are stored in C:\Users\...\AppData\Roaming\Thunderbird\Profiles\...\Mail\Local Folders\Sent.sbd\Gesendet

It appears to me that this behaviour is related to a bug in Thunderbird 115.01.

It appears to me that this behaviour is related to a bug in Thunderbird 115.01.

Did you get it sorted out? File a bug report?

The situation with my sent messages remains as before: If I use the alias "name"@nexgo.de the message sent is copied into the sent folder ("Gesendet" in German. If I use any other alias or even the account name "name"@arcor.de the message sent is copied into the local folder "Gesendet" ("sent"). As mentioned before this appeared only after installing Thunderbird 115.01 that has been automatically updated to 115.2.2 now.

I haven't filed a bug report since I don't know how to.