At the very least Microsoft could have given us some system-wide notification that there were problems...
Anyway, this is what status pages are for: https://admin.microsoft.com/servicestatus (currently showing a whole lotta information about problems with Microsoft Teams).
To your specific suggestion, how do you identify if the messages arrived late because of a server-side issue, rather than a client-side, network disconnect, or some other non-infra issue?
Anyway, while I'm sure there's myriad ways that the authors of this app could have engineered it to be more resilient, self-reporting, etc - it's clear that they did not.
The implication is that the infra required to notify of an outage is lesser/different than what’s required to…run Teams. Publish it on DNS!
I'd also assume if you're using Microsoft Teams it's because someone else has determined that you shall use it. I expect that any semi-informed, mildly IT literate Microsoft Teams user has a starting position of 'low expectations'.
Anyway, parent was suggesting an in-app message to indicate some issues, so my initial question stands - how do you expediently send an instant message to a user to advise them that your instant messaging app is having a bad day?
1:23 Coworker: Hello
1:24 Me: Hello
[20 minutes elapse]
1:44 Me: Did you need something?
[No notifications until leave for the day]
[Checks back hours later and the conversation appears as]
1:23 Coworker: Hello
1:24 Me: Hello
1:25 Coworker: Could you herp the derp?
1:30 Coworker: Nm got Mo to herp the derp.
1:44 Me: Did you need something?
1:45 Coworker: Nah I'm good.