NEW YORK (CBSNewYork) — A deadly mistake took the life of a canine social media star, and her two biggest fans were left heartbroken.

The Manhattan dog Chloe the Mini Frenchie won the hearts of thousands of people on Instagram, but died unexpectedly at a local animal hospital – leaving her two humans heartbroken.

They spoke with CBS2’s Jessica Layton Thursday night.

“She had such an impact and made so many people happy – and she’s our little baby,” said Loni Edwards.

It was a pain that Loni Edwards and Phil Toronto never saw coming.

“A nightmare — it’s unbelievable, walking into this apartment,” Edwards said tearfully. “That’s the hardest part.”

For four and a half years, Edwards and Toronto’s apartment has revolved around their adorable 14-pound pup with a larger-than-life personality. But on Thursday night, the doggie bed belonging to Chloe the Mini Frenchie was empty, and the dining room table was overflowing with sympathy flowers.

The Instagram-famous dog died on Wednesday during what should have been a routine precautionary procedure at BluePearl Emergency Pet Hospital in Chelsea.

“They messed up,” Edwards said. “They put the oxygen right into her without calibrating it, and it exploded her lungs and caused multiple cardiac arrests — and killed her.”

Chloe was taken to the facility for observation after surgery.

“The initial surgery was to remove a piece of her soft palate, which is a very common surgery,” Toronto said.

That surgery at a different location went well. But the fatal mistake that followed at BluePearl was unexpected by everyone.

Edwards shared the upsetting update in a post on social media.

Chloe’s fans were clearly heartbroken.

A representative of BluePearl told CBS2 it was a medical error that shouldn’t have happened. She said the animal hospital was taking immediate steps to make sure nothing like it ever happens again at any of their facilities.

“It’s obviously nice to hear that they’re admitting what happened — but it’s not bringing her back,” Edwards said.

But Edwards and Toronto know the joy Chloe brought them, and her thousands of followers, will always be in their hearts — even if she is no longer at their side.

Edwards was supposed to take part in a fundraiser this Saturday for dogs being rescued in Puerto Rico. The event will now serve as a celebration of her life.