@Nanxing0
I've never had a co-host, so I don't know about that, but it seems like a pretty basic error.
I did contact Airbnb several times about not getting my message notifications, but they keep denying anything was wrong. Usually they told me it was my phone and to delete and reinstall the App, but this is the third phone I am using since I started hosting and they have all been different (Samsung, iPhone, Huawei), so I know it's not that.
The last rep I spoke to about it was beyond clueless. I explained over and over that I was not getting all my notifications and the ones I was getting were often severely delayed. She just kept responding, "So, what you are saying is you're getting too many notifications? You know you can just turn them off?"
I eventually gave up, telling her not to trouble herself about it...