Hallo,
all is working on my own server, but on the customer server I do get the following message:
The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET MAX_JOIN_SIZE=# if the SELECT is okay
Customer support of the server told, they can not chance this, but I can chance in the file.
But I do have no idea in which file I should chance this??

Found the solution: o fix it i just have to edit the file libraries\joomla\database\driver\mysqli.php
and to insert the line
mysqli_query($this->connection,"SET SQL_BIG_SELECTS = 1;" );
in the function connect after the line 168( mysqli_query($this->connection, "SET @@SESSION.sql_mode = '';")

Problem solved.