A few questions/notes...
Are you crating the new pup?
Are you catching her in the act?
How do you react?
The pup can't "hold-it" as long as an older dog.
A pup that young doesn't "know" it needs to poop
!, until it is doing it!
As soon as her eyes open, after a sleep, walk her straight to her potty spot, keep her there until the mission is accomplished. Then have a party for her! Treats, loves, snuggles... Then have a play, fast and furious, if she slows down, potty her again! Try not to have accidents, and have lots of party's!
Good luck!