I usually manage to fix it by:
- open settings
- search for "Trusted Agents"
- turn google off
- restart phone
- turn bag google agents on
But in general i need to repeat those steps after every google app update I think
Just came back from work,
i have tried to do the same way with my P20, it is not working too.
However, when i do the same for my Samsung S8+, it works!
which means voice activation for S8+ is working but not P20
I can't activate voice match at all. I've tried multiple different languages (phone and Google app) but the setting is always greyed and unclickable. Tried different fixes but no success.
Unfortunately Smart Lock has been broken in all the Android devices for a while now, and Google just doesn't seem to care. It's not an issue with Huawei phones.
Please star the issue and write a comment here, hoping one day they'll address it... https://issuetracker.google.com/issues/65972290