Using ReCaptcha from project A in application from project B in Google Cloud

The Invalid Sitekey issue is most likely due to not having configured the correct package name for that site key.  Or using an "OnPlay" site key on a non GMSCore device, such as a device in China or a Fire device etc.  

reCAPTCHA operates independently of Firebase's relationship with an app, so that shouldn't have anything to do with it.

Thanks for the reply! 

1. It can't be the package name, it's correct, and for checking i,t even more,e I disabled the package name verification - still getting the `Site key Invalid`. 
2. I am getting that error on my physical phone, with Google Services and I am not in China. 
Do you know if there are some additional checks for compatibility like SHA-1 fingerprints in Google Cloud project inside the Android SDK? 

I implemented recaptcha already in project B inside a different app. In project B in a console,I have the Recaptcha API configured. 
In project A, I have a new app where the problem occurs. 
Any thoughts? 

The SDK does not check for ownership of the app in those ways. The requirement is that the site key match the package configuration and what is sent by the app.  I know you have checked, but there is probably a mismatch (copy paste error etc). 

If you post your site key and what you believe your package name is I will try to take a look at our logs.

You state that the package name is incorrect, but as I said, the error still occurs even though I disabled `package name verification`.  So it can't be the package. If it's not the package, then there are some additional requirements for the site key to match. Are there some Play Integrity checks during the recaptcha token retrieval on the Android side? 

Post a site key? Do you mean posting a name or the value of a site key? I believe it's not safe to share the site key here. 
Project name: KingsChat
Site key name: Android Production Kingspay
Site key required package name: 
com.kingschat.kingspay
My app package name: 
com.kingschat.kingspay

We don't view sitekeys as sensitive.  They are easily found in binaries (and even appear in the html of every website using reCAPTCHA).  Is it possible you are trying to use the old key from your Android v2 integration (ends with k9xAO). That would also cause this issue.

It looks like you created new V3 keys yesterday and have assessments attached to them.

If so, this is the key I try to use: 
*******************************. 

I'm certain I don't use the old key from Safetynet for the new recaptcha Enterprise client. You can see that the key I mentioned is displayed as correctly integrated. It is working fine, but not on the builds that are signed by Google Play. On my local builds (staging/production and release builds) it works fine. 

I looked through the logs for events related to that sitekey or related to your package name.  I see lots of "no network" errors from your roboelectric tests, and some success from an emulator, but no exceptions for bad sitekeys.  There are less than 100 attempts to init the SDK.

So not really sure what is going on with your app.

Yep, it's not released to the whole audience, that's why there is not much attempts. 

Am I able to see those logs also somewhere in the console? 🤔 🤔

Hey @markcorner , are you sure that it's possible to use a site key from outside the app project on Google Cloud? 
It is weird that the recaptcha works when the same app build is signed locally(release key from Android Studio), but when installed through Internal App Sharing (Google Play) it doesn't work and returns "Invalid Site Key". 
Any thoughts on why I have such behaviour? 

All problems were caused by my fault. It was not a problem of play app signing, but building the app on CI system. My service account used on CI didn't have the permissions to access the recaptcha site key. So in result, the site key I was using on that build was empty. 
Thanks for the help @markcorner and sorry for taking your time. 

No worries, I am glad you sorted it out.  Perhaps this will help someone in the future.