I bought TT online this year (2020) but TT never asked me to file a GA state income tax. Why did it tell me to last year and had to pay a tax due amount for GA. Why? Did I file incorrectly last tax year?
Rental income from property located in Georgia is definitely taxable by Georgia. Go back to the Personal Info section of TT and make sure that you indicated that you had "Other State Income" from Georgia.
It is not all that common for residential rental real estate to actually show a taxable gain on paper at tax filing time. Especially if there's a mortgage on the property. When adding up the deductible expenses of mortgage interest, property taxes, property insurance and taking the depreciation into account that you're required to take by law, those four items alone will usually exceed the total rental income received for the tax year. Add to that the other allowed rental expenses such as repairs and maintenance, and you're practically guaranteed to show a loss on the SCH E.
Take a look at line 26 of the SCH E. If it shows a loss, (which I would expect for residential rental property) then you don't owe taxes to GA on that specific income.