The Code tab does not show up, when a user with the correct profile is logged in.

Please post a screenshot of the editor toolbar.

This is what i see, when i create a new content or edit existing content.
Additionally i posted the setting that the code editor is activated in a profile

By the way, we use Version 2.9.27 of the editor.

Please send me a login - https://www.joomlacontenteditor.net/contact/site-login

The problem is solved (halfway).
Our customer uses the editor with his account and the activation of code editing solved the problem for this account.
There seems to be a missconfiguration for my testaccount, but i cannot see what causes the problem.
The configuration is very complex in a multidomain environment with seblod.
For the moment the problem is solved for our customer.
There is no need for further investigation on your side.
Thanks