no database connection

What is wrong and how to address this?
I am getting this error message:
Using Connection String:
Host=localhost; Database=….; Uid=….; Pwd=….; Port=3306
Host: Fail
Database: Fail
Version: This Server: [no connection] — Package Server: [5.5.31]
NOTICE: In order to avoid database incompatibility issues make sure the database versions between the build and installer servers are as close as possible. If the package was created on a newer database version than where it is being installed then you might run into issues.

It is best to make sure the server where the installer is running has the same or higher version number than where it was built. If the major and minor version are the same or close for example [5.7 to 5.6], then the migration should work without issues. A version pair of [5.7 to 5.1] is more likely to cause issues unless you have a very simple setup. If the versions are too far apart work with your hosting provider to upgrade the MySQL engine on this server.