Potty training help

I rescued a puppy almost 3 months ago and she's been doing great with learning new commands but I cannot get her to use the bathroom outside. Her previous owner would let her use the bathroom in the house and have no repercussions so I feel like that is a huge part of the problem. I have her on a schedule and I've tried putting her on a leash in the backyard and walking her around hoping that'll help but she literally will not use the bathroom outside. We could be outside for five minutes or 30 minutes and the second we come inside she uses the bathroom. I've cleaned with white vinegar and natures miracle, but that has not stopped her lol. I've had dogs my whole life and I don't remember potty training being this hard so if anyone has any tips or tricks, please share I'm struggling lolol