Incorrect error messages when opening emails

[GVodyanov]

Steps to reproduce

1. Have an email not being able to be parsed and opened

Expected behavior

2. An error message with something like "Email not able to be opened"

Actual behavior

3. It says "Email could not be found"

Mail app version

main

Nextcloud version

No response

Mailserver or service

No response

Operating system

No response

PHP engine version

None

Nextcloud memory caching

No response

Web server

None

Database

None

Additional info

No response