我已使用Firebase函数发送通知。当我的android应用中发生动作时，将触发Firebase函数。它有时发送通知，有时却不发送。由于我已经对它们进行了彻底的测试，因此代码中没有错误，并且日志中未显示任何错误。它有时根本不发送通知。我不明白为什么在某些情况下会发生这种情况。
正确发送通知时记录
11:44:03.928 AM myFunction Successfully sent message: { results: [ ...] }
11:43:36.328 AM myFunction execution took 1002 ms, finished with status: 'ok'
11:43:36.304 AM myFunction Function returned undefined, expected Promise or value
11:43:35.327 AM myFunction Billing account not configured. External network is not accessible and quotas are severely limited. Configure billing account to remove these restrictions
11:43:35.327 AM myFunction Function execution started
在功能触发但未发送通知时记录
10:55:57.710 AM myFunction Function execution took 920 ms, finished with status: 'ok'
10:55:57.688 AM myFunction Function returned undefined, expected Promise or value
10:55:56.791 AM myFunction Billing account not configured. External network is not accessible and quotas are severely limited. Configure billing account to remove these restrictions
10:55:56.791 AM myFunction Function execution started
请帮助解决为何触发该功能以及有时不发送通知的问题，以及如何解决此问题。提前致谢！