Hi!
I have come across a couple of issues with sendMail.
These two episodes happened when trying to connect to smtp.gmail.com or smtp-relay.gmail.com, on Windows and with vibe.d 0.7.23
On windows, at least, I cannot use startTLS or ssl connection modes. I always get an openSSL decode error. I tried all combinations of startTLS/ssl and sslVertificationMode as suggested on couple github issues I found, but it still failed. It could be I just need a new OpenSSL version - currently using the one distributed with vibe.d which is 1.0.1j. I cannot say if this happens on linux or with a different OpenSSL version, and unfortunately time is of the essence, so I can't investigate further.
So then, I tried to connect with a plain connection on port 25 and at this point no auth method was working - I always get back "Bad command sequence". I looked briefly in smtp.d and it seems like the auth commands are sent in a different way than what is mentioned in the RFC, but I could be wrong, and again, no more time to spend on this.
I went with only IP authentication which is a bit more troublesome for me - need to constantly add dev IPs and staging/production IPs to a list, but it's working!
I'm, sorry I couldn't investigate any further, but time is really tight at the moment!
Just thought I'd share these in case someone runs into issues as well, or maybe someone might have helpful comments.
