It is a cautionary tale for the rise of the so-called “internet of things”: some pets could be left hungry after a server outage appeared to be causing automated feeders made by a company called PetNet to malfunction.

The lesson: always build a backup system.

PetNet describes itself as “the world’s first intelligent pet feeder that will program itself around your life and the wellness of your pet. The $149 device links to a smartphone app so that, in theory, customers could rest assured that their pet was well fed while they weren’t home.

But a server issue has taken down the system for a number of users, leaving many animals without their scheduled meals.

In an email to customers which was posted to Twitter, the company said: “We are experiencing some difficulty with one of our third party servers. This is currently being investigated.” The email said that customers should “please ensure that your pets have been fed manually” until the issue could be resolved.

But this has caused anger – at the height of vacation season – because many PetNet users rely on it when they leave their animals alone for days at a time and might be unable to return to feed them.

spend $150 on a fancy pet feeder that doesn’t feed your cat when their servers are offline what a great design pic.twitter.com/ZXMiGuWNFE — Alan (@alanzeino) July 27, 2016

PetNet’s CEO, Carlos Herrera, told the Guardian that the third-party server service, which he said the company rents from Google, had been down for around 10 hours and did not have redundancy backups, but said that PetNet was preparing to roll out a workaround to the problem.

Herrera claimed that about 10% of PetNet users were affected, and that the feeders can operate on previously set schedules without this particular third-party service, though users lose the ability to feed remotely or change the feeding schedule.

Taryn Studer, who has used a PetNet feeder since February and is being affected by the outage, said that many users might not even know there was an issue. “Most are unaware as their emails go to spam or are filtered and we didn’t receive alerts on our phone that the auto feed was down,” she said.

“I have a cat named Winston who loved this feeder,” Studer said in an email. “It would appear that despite my device being connected to wifi and appearing to work perfectly (we usually receives notifications to feedings not working but this is not the case with this issue), I have to manually feed him.”

“This has sent me into a panic as I am a college student with multiple jobs and rely on this device to make sure he receives proper feedings and nutrition,” Studer continued. “I have had to arrange for friends to get keys from me at work if needed so he will get his food.”

Studer said that for her, the most upsetting thing had been the customer service response, which she described as “completely dismissive and unapologetic”, saying that their phone line went unanswered and her emails have either been ignored or replied to with a generic response.

“This product was my absolute favorite thing and I highly recommended it to anyone who would listen,” Studer said. “However, this customer service experience has left me very wary to consider using the feeder and I still don’t have answers as to when it will be operating.”

“I understand a company-wide server outage is difficult to handle, but this is absolutely ridiculous when the lives of hundreds of pets are tied to their product,” she added.