Why did Boston newspaper call the years of James presidency era good feelings?

There is no evidence to suggest that any Boston newspaper referred to the years of James Madison's presidency as the "Good Feelings" era. This term was coined much later, in the 20th century, to describe the period from 1815 to 1825. Madison's presidency actually coincided with a period of significant political turmoil and divisions, including the War of 1812 and the Hartford Convention.