Send from subaddresses
You can receive email at subaddresses like
<tag>as described in the docs, but you can't send outbound emails from such subaddresses.
This is problematic because it confuses recipients when they get a Reply from a different email than they put in the To box. Customer support systems in particular seem unusually sensitive to this kind of mismatch where support staff can't find the original ticket because it's associated with a different address.
With Roundcube you can create new Identities and attempt to send from these subaddresses, but the cloudron server rejects it as not allowed.
This limitation has been acknowledged in the past:
Like email@example.com, firstname.lastname@example.org and so on. This way, they all land in the same mailbox email@example.com. ... But this way, you will always reply as firstname.lastname@example.org (and FROM will not be email@example.com).
This request is to change this behavior to allow sending from subaddresses.
Oh cool thanks for pointing that out, I hadn't noticed before.
I guess the downsides don't really apply to me right now, but I'm not sure I'd want to enable arbitrary masquerading if there were a bunch of other people on this cloudron.
I still think it's reasonable for users to be able to send with a subaddress of any of their aliases, without opening the floodgates and allowing them to send from any address at all.