Puppy and pooping training

Greetings r/puppy101

So, we got a two month old Cocker Spaniel. I've had Cocker Spaniel for fifteen years before this one and the dog was a delight to train, she learned very fast to go outside and poop – but this one is a complete opposite so I'm asking here for some advice.

The puppy is with us for about two weeks, she had her vaccines, but every time we go outside she simply sits in place and shivers, won't budge for a minute or two then when I call her she'll take few steps to come closer and again just stand still and shiver; so far that's what our walks have looked liked. Whenever outside she simply won't play, won't urinate or poop – but the moment we get in the house she'll relief herself in the hallway and play completely normally. When I notice she's sniffing in circles, I pick her up and move outside and she'll again just sit and simply won't budge – I stay with her for half an hour and she'll eventually start sniffing and exploring, but just simply won't relief herself – then we get in the house and again, she'll immediately do it indoor. When she did relief herself outside I immediately offered her treats, but she simply didn't want them – just sniffs them and backs away. I still praise her and cuddle to reward her but it's strange she won't have her treats.

The treats aren't an issue, because whenever I offer them indoor she'll take them without a problem. It's like when we get out she's a completely different dog, she follows me in the house wherever I go – even now as I type this in my study room she's by the desk sleeping; but when I tell her "Let's go for a walk" and bring the harness and leash, she starts shivering and clearly shows she's unwilling to go outside. The outside is relatively quiet, there are other dogs as well in other people's yards but none of them really bark or do anything that could scare her.

I even have training pads and drops in house, but most of the time she'll just ignore it – sniffs and carries on, goes to kitchen for e.g. and reliefs herself there. Am I overreacting because of previous dog's quick learning? She comes when I call her, knows how to sit, etc. but potty training and walking are a real problem with her….

Any advice will help, thanks a lot.