Hi Ralf,
Thanks for reaching out.
Sometimes the only screenshot does not help us to recognize the issue you are having, but your screenshot shows a broken HTML, where the <span> is not properly closed, that might be the reason behind your issue. Please find the screenshot marked with the issue.
Please also check the Title section, which may consist of the same. If that is not the case, please provide login credentials for your site in a secure note to examine it further, including:
– WordPress Site URL & Login URL
– WordPress Admin username/password
To create a secure note, click the key icon underneath any of your posts.
Thanks