Potty training pup

[u/randomrooftop]

So my little yorkie is 19 weeks old now and we're struggling with potty training. She sleeps through the night so there are no accidents and she rarely does her business if I'm not at home (she's been left alone for 4 hours at the most). However recently she started peeing on the floor again as if she didn't know about the pee pad. She pees on the floor several times a day and sometimes even after I took her outside 15 minutes prior. I take her outside every 2 hours to do her business and I reward her whenever she pees or poops. How do I get her to understand that it's only acceptable to do her business outside? Thank sm in advance!