Notifications not working for some users

Description

We have ~70 people using RC, several have said that they are not receiving email notifications with new messages (even though they have selected for it in different channels).

I’ve been trying to work this out with two accounts - my main admin account and an extra email with just user permissions.

Admin account: stopped receiving email notifications about two weeks ago (including messages, direct messages, and mentions). When I switch the email notifications setting in a channel to ‘All messages’, I still do not receive any email notifications (even mentions). Email notifications setting switches to default whenever someone else posts in the room. I still receive admin emails (e.g., new user needs to be activated, SMTP test email).

Other account: Switched email notifications to ‘All messages’. When someone posts something in the room, the email notifications setting switches to default. However, I continue to receive email notifications for all messages, mentions, etc.

Admin setting for offline email notifications is set to DMs/mentions as is the individual notification settings in preferences.

Server Setup Information

  • Version of Rocket.Chat Server: 3.18.3
  • Operating System: Ubuntu 20.04
  • Deployment Method: Snap
  • Number of Running Instances:
  • DB Replicaset Oplog:
  • NodeJS Version: v12.22.1
  • MongoDB Version: 3.6.14 / wiredTiger
  • Proxy:
  • Firewalls involved:

Any additional Information