This error message can show up when one of the system emails fails to be saved in your database. This can have various causes, such as a full database, a missing column, a security that rejected the content, etc…
For now, you could click the “Nein, danke” link at the bottom of the page, then the skip link at the top-right of the next page.
You could also take a look at your database error logs file if you have access to it in order to find the cause of this error.
In this error message, the prefix seems to be missing the trailing “_”. Or maybe all your database tables have “wp_skcit_com” as prefix?
You can open the file wp-content/plugins/acymailing/back/tables.sql to find the tables creation queries we use to create our tables. Note that all occurrences of “#__” must be replaced by your database tables prefix (be it in the table names or the constraints).