All google.com URLs are blocked in China. Since all Firebase links use google.com, it is pretty much guaranteed that no part of your application can access any Firebase services when used from within China. You can use simulators such as → Dotcom Tools to understand the availability of Urls from China.
Alternatively, you can read here how to get a Chinese VPN address and then simulate access to Firebase services from here → [VPN to China]. 2
But also note that the Google Playstore is not available from China. Thus, users in China cannot download the Android app and (if you are not iOS).
So, you will need to find an alternative mechanism for distributing and launching your application for the Chinese market.
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