It appears that ‘Okay Google’ detection has stopped working for a number of users.
Overall the issues appear to primarily affect Xiaomi, OnePlus and Samsung phones. The phones no longer respond to the ‘Okay Google’ voice prompt and options to turn on voice control aren’t accessible.
However, Google is aware of the problem and is working on a solution.
In one of the Assistant Help forum posts, Google employee ‘Andy B.’ said the company had identified the problem. Furthermore, the search giant was pushing out a fix to most users. The update should finish rolling out in the next few hours.
Some users are already reporting things are working better. Others have offered their own solutions, from uninstalling the Google updates and trying again to activating Assistant manually. The latter seems to remind the Assistant that it has a trained voice model and for some users makes it respond to their voice again.
Other users suggested it was related to the different Assistant voices. Changing the voice reportedly fixed the problem too.
If you’re affected by the problem, rest assured that a fix is on the way from Google. If you’re impatient, you can try one of the other solutions as well.