how to get my 61/2 month old rescue to not pee on the couch?

we are her 4th family, she has a crate she likes leave the door open. she will go in and out a dog door will pee outside always the same place is praised and rewarded with training treats for peeing outside. She peed out side this morning came in after 2 hrs I took her out on a leash to pee she would not. Came in and have barricaded the spot she had peed on twice she squatted and peed next to it. I don't know what to do can't have her destroying the furniture. Any suggestions?