[SOLVED] I kind of figured it out by doing some minimum amount of bank transfers, I concluded that the only needed domain in order to make push notifications work for my banking app is mtalk.google.com.

Not sure if it’s totally right tho. It worked for me.

I found this post on /e/OS forum: https://community.e.foundation/t/what-are-mtalk-google-com-and-www-googleapis-com-serving-for/4788/5

mtalk.google.com is needed by GCM (cloud messaging). For those using adblockers it was always recommended to whitelist it (not block it), otherwise one would have problems with push messaging

[OP] I’m currently using a ROM with GrapheneOS sandboxed Play Services + DNS filter with No Google list that blocks everything from Google.

But I think it’s worth the trade off of whitelist just a specific domain because I really need instant push notifications from my banking app.

But since I blocked everything I think it’s not reaching Google servers to handle push notifications properly.

So if anyone could help on this I really appreciate it.

I see my bank trying to reach these domains:

• firebaselogging.googleapis.com
• firebaseinstallations.googleapis.com
• firebase-settings.crashlytics.com

(I just pause the DNS filter when I need something related to Play Services)