Since chat mail accounts are deleted automatically, error messages while sending happen more often.
Especially in bigger Groups it can become a problem, since you see email addresses in the error, but you don’t see those email addresses in the group member list, so it is hard to find out which members you need to remove from your group, to not get delivery errors on your messages.
See "User does not exist" errors · Issue #5173 · deltachat/deltachat-desktop · GitHub for more details and screenshots.
Solution ideas
The desktop issue discussion revealed two possible solutions, both need parsing of the error message and remembering/collecting the failed addresses. (AFAIK currently message-info only shows the last error, so if multiple recipients don’t exist, you would only see the last missing repient.):
1. highlight broken users in group member list
one possible solution would be to add the “error” mark in the users list of the channel or group them into a separate region in the listing
~ trufae in "User does not exist" errors · Issue #5173 · deltachat/deltachat-desktop · GitHub
2. show in Read Receipts UI
Wofwca suggested adding failed users to the Read Receipts list.
Workarounds
- copy email address from error and use the global search to find the contact associated with the email address.
- (too much work in large groups) click though all members in memberlist to compare the email address manually (which appears in the profile view)