For unaccessible URLs: don't try to display a preview, display just the URL
When posting an URL into Microsoft Teams using the desktop client, an error appears (instead of the website preview) saying "404 — Error Message" whenever the URL is inaccessible for the O365 cloud infrastructure.
This is quite an issue, because all the links to our internal, on-premise applications will end up in an HTTP error 404. And all the links to external applications that need authentication, probably in an 401...
My suggestion is to add a configuration switch like "For URLs that end in HTTP errors: don't try to display a preview, but display just the URL entered".
Sean Ellis commented
Agreed. Also, whether URLs show previews at all should be configurable (if they aren't already). Should be configurable per-channel.