California recently launched a new tool that allows fully vaccinated people to create a digital copy of their vaccination card.
However, many are experiencing problems retrieving it or are simply not aware of it being an option.
Bay Area resident Mary Rodriguez wears a pin to show others she's fully vaccinated.
"So that way everybody knows I’m doing my part to keep everybody safe," she said.
Many people say they've heard of various difficulties while using the app.
In some cases, people are being told the state has no record of their vaccination and others get a QR code with the wrong information.
The state vaccine task force explained the most likely cause is a data input error; either phone number or address were entered incorrectly or illegibly when getting a vaccine's first dose.
NBC Bay Area reached out the state but no one was available for comment.
Those who don't want to wait for the state to fix the app's bug have come up with a plan B - snap a photo of your vaccination card.