Firewall rules for outgoing traffic from gorush to fcm

https://firebase.google.com/docs/cloud-messaging/concept-options#messaging-ports-and-your-firewall

This list is for incoming push messages to user devices behind firewall. I need list for gorush push sender.
My gorush server is behind firewall and I need a list of domains to send push messages to FCM. Right now I get some from different sources, but It don't work and in logging I don't get domain names I stuck with. Ports 443, 5228-5230 opened. Can you add log messages for domain name gorush get timeout or answers with errors?

my current list for outgoing domains for push traffic from gorush to FCM is this:
-fcm.googleapis.com,
-www.googleapis.com,
-account.google.com,
-oauth2.googleapis.com.

where can I get list needed for gorush to function? I don't find FCM doc for this topic yet.

Start with the linked Firebase Cloud Messaging documentation and inspect gorush’s outgoing FCM request and logging behavior. Identify the domains required for FCM traffic and determine how timeout or error logs could expose the affected domain. Done means the required outgoing destinations are documented and the requested diagnostic logging behavior is specified and tested.

Written by the indexing model from the issue text.