Clerk firebase authentication causing firebase login to fail.

[mileslow]

our company follows the firestore / clerk authentication integration guide, and we are experiencing a problem plaguing our users.

Taking a look at the snippet from clerk:

`const signIntoFirebaseWithClerk = async () => {
const token = await getToken({ template: 'integration_firebase' }) // runs successfully for us

const userCredentials = await signInWithCustomToken(auth, token || '')  // this fails to run, takes 30 seconds, and then fails
// The userCredentials.user object can call the methods of
// the Firebase platform as an authenticated user.
console.log('User:', userCredentials.user)

}`

the error that is outputed:
FirebaseError: Firebase: Error (auth/network-request-failed)

and it only occurs after 30 seconds.

This issue is NOT replicable, and happens to random users randomly, when this happens no amount reloads fix the issue.

Does anyone know what could happen or what could possible cause this?

[wobsoriano]

Please see #3829

thanks!