thank you!
changing the admin folder name worked now, it seems that only lower case letters are accepted here
when I do a check in mysql the following is displayed
mysql -u root -p -e "SHOW VARIABLES LIKE 'sql_mode';"
+---------------+-------------------------------------------------------------------------------------------+
| Variable_name | Value |
+---------------+-------------------------------------------------------------------------------------------+
| sql_mode | STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
+---------------+-------------------------------------------------------------------------------------------+
It seems the strict mode is already off, but the health status shows a message to turn it of in /etc/mysql/my.cnf