Another one bites the dust for bankrupt Toni Braxton ... the singer's Georgia mansion -- the one she desperately tried to save from foreclosure -- is officially up for grabs to anyone with a spare $1.1 million.

Braxton took out a loan for the Duluth, GA crib back in 2004 for $1.5 million -- but according to the bank, she failed to make at least 10 monthly payments between 2004 and 2010.

As TMZ first reported, the singer filed for Chapter 7 bankruptcy in 2010 -- during which time she tried to save the home from being sold off. It didn't work.

Here's what she's losing ... 11,400 square feet, 6-bedrooms, 6-baths, an acre of land, jacuzzi tub, gourmet kitchen and a library.

FYI -- This is the second house Braxton lost to foreclosure. Her Nevada pad was sold off back in 2010.