With the introduction of deep links, we now increase the probability of hitting channels and permalinks via erronenous cases:
Deep link example:
Bogus server URL
Malformed channel ID (i.e. non-existent channel)
Malformed permalink ID (i.e. non-existent permalink)
Private channel not belonged to (partly handled by changes in MM-21068)
Permalink to message in private channel
Public channel that one doesn't belong to
Team not belonged to
Links to Group messages and DMs
The default error handling in these situations is often to fail 'silently', and leave the user back at the channel where they last were, with no feedback about the failure.
Bring up an error popup, describing the link failure.