Firebase Messaging throws exception and doesn't get back until server restart

I have a system built with spring boot, java 8 and hosted on google cloud using compute engine.
My server app is wildfly 21.0.1.Final.
I am using firebase messaging 9.1.1 to deliver notifications to the application users.
The service is working fine most of the time, however, I get this error from time to time.

` com.google.firebase.messaging.FirebaseMessagingException: Failed to establish a connection: Error getting access token for service account: IP_OF_PROXY_HOST_GOES_HERE, iss: firebase-adminsdk-project@projectname.iam.gserviceaccount.com`

As a workaround, I do a full server (wildfly) restart to get the service back.

In my pom file, I have:

com.google.firebase
firebase-admin
9.1.1

I have searched for similar issues and checked:
1- The system clock is synchronized
2- Firewall access to firebase
3- The service works well and the issue happens randomly from time to time.
4- I can not reproduce since I don't know the cause.

Note: I don't use any other firebase service in this product.

Does anyone know what is happening and how to overcome this issue?

从 pom.xml 中对 firebase-admin 9.1.1 的依赖开始，跟踪服务账号访问令牌失败时的 FirebaseMessagingException 路径。收集间歇性故障期间的日志，并比较 WildFly 重启前后的行为；完成标准是确定一个可复现的原因并记录可靠的修复方案，或确认这是 SDK 问题。

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