Grafana Alerting is unstable

I installed grafana on IoT PC in my plant.
Problems are as follows,I built grafana system with portaiar Docker.
When I register the email addresses of Mr. A and Mr. B in the Email Alert Settings,I send a Test with Alerting Notification Channel
Then the following four phenomena occur.
A. Alerting only to Mr. A
B. Alerting only for Mr. B
C. Alert for both Mr. A and Mr. B
D. No alert for both Mr. A and Mr. B

Until around the summer of 2022, the app was working properly with a password that allowed email manipulation from the app after 2-step verification of G-mail.
After that, no more outgoing emails were left in the outbox and I had to forward them from Mr. A’s email, but no more incoming emails were left in the inbox either.