As you can see from the error message:
Access denied for user 'sitefinity'@'%' to database 'sitefinity'
Seems the user does not have appropriate permissions for the database. Please, give him the permissions. Also, along with the permissions for the project database, the user should have permissions for mysql and information_schema databases.
Or, you could use the 'root' account.
Hope this is helpful. Please let us know if you need further assistance.
All the best,
the Telerik team