You need to share more information. is this an IMAP account? what are your settings in the 'copie&folders' screen? Can you do a screenshot of your folder pane?

It is a POP server

Can you post a screenshot of the folder pane, and of the copies&folders pane? That may help.

I´ve tried.But there is no poossibility to take a screenshot.Sorry

I´m missing following folders: Gesendet;Archiv;Junk and Spam

If you set up a new pop account, Thunderbird initially only creates the Inbox and Trash folders by default. Sending a message will create the Sent folder, the Drafts folder will be created when writing/saving a message. The same for the Archives folder: it will be created when you archive one or more messages. There is no "Spam" folder in a POP account of the German Thunderbird version, but you can use the Junk folder after activating it in Account settings > account name > Junk Settings

Für Bildschirmkopien siehe https://support.microsoft.com/de-de/office/kopieren-des-fensters-oder-bildschirminhalts-98c41969-51e5-45e1-be36-fb9381b32bb7