Driver Directory - Failed to save

I copied the JDBC Drivers into the main Confluence folder and put it into a folder "MySQL". the path now is sth like:

/opt/Company/confluence-Company/atlassian-confluence-6.12.0/MySQL/mysql-connector-java-6.0.6.jar

Then I have tried set the Driver Directory to "/opt/Company/confluence-Company/atlassian-confluence-6.12.0/" and an error pops up "Failed to save the configuration. Please try again." and refreshes the page. Any other path I tried did not work aswell.