Failure to indicate that messages could not be sent

### Your use case

#### What would you like to do?

I had to change some of my configs related to the `.well-known` but did a mistake that leads ` /.well-known/matrix/server` and `/.well-known/matrix/client` to return 404. It is obviously a problem, and I didn't received any message anymore. After some times, I realized that it was surprising that I didn't receive any message and the people I sent some to didn't read it. When I looked into the server's logs, I saw an error message.

But on the frontend, everything acted like it was fine, that my messages were sent, but they actually weren't. It would be way nicer to have some kind of warning in this case, that the server/the correspondant server couldn't be reached, and thus the message wasn't really sent.

#### Why would you like to do it?

To directly see that there were a problem, without element telling me that everything was fine.

#### How would you like to achieve it?

I don't really know who, between the client and the server, could detect that, but at the end, the client should show a warning on the message or the conversation.

### Have you considered any alternatives?

I read the logs, but it's not really convenient.

### Additional context

_No response_