Hi,
Since you can access the Kentico site you are trying to apply the hotfix to without any issues, the connection string and database are correct. Perhaps the KIM is using a different user account to access your database and doesn't have correct
permissions to connect?
You can
download the hotfix package manually and run the installer, which will generate the SQL script file in the following location -
C:\Program Files (x86)\KenticoCMS\7.0\Hotfix...\SQL. You can then execute this file directly over your SQL database to finish applying the hotfix.
Please let me know if you have any additional questions.
Thanks,
Sandro