And it's ok. It's the way we've been writing software since forever and bugs have never been something that stopped us.
Accessibility is essential in product development. But it would be silly to think you'll create a product that works all the time for everyone, flawlessly. No such thing! Bugs are part of the deal. Better yet, they're essential to the journey. Only through mistakes will we learn.
Accessibility bugs, maybe missing alt text or some ARIA roles you shouldn't have used, are common. You'll create these issues for whatever reasons. Maybe a lack of awareness, maybe you didn't understand the guidelines or the technology shifted from underneath your feet. That's ok.
How you move forward though is crucial. You can deny these bugs exist. You can throw up your hands in despair and think that accessibility is pointless.
Or you can sit down with your team and figure out what went wrong, how you can fix it now and how you can prevent the same thing from happening later. Maybe the team needs training. Maybe you need to address the lack of tools. Maybe you should involve diverse testers in the process.
You can start small, build your knowledge as you go and use available resources like the WCAG and the ARIA documentation to guide you. Since accessibility isn't a one-time fix, only by having a proactive approach will you be able to catch and fix issues early.
To err is human and it’s ok.