Looks nice.
Printing statements from a class might be considered strange in certain cases.
If I was to use this from another program I wouldnt want it to be interactive.
In that case it might be better to actually do the config from a parameter perspective, at least that is what I would do.
For example; Mail.config(PROVIDER=default,PASSWORD,USERNAME,TYPE=default)
Again this is personal but I would use the class as a template and the 'data feeding' seperate.
Or maybe Im just plain wrong, anyone with more insight ?