We have a sendmail relay sitting between our gwia and the outside world.
Communication between sendmail and gwia is encrypted if I enable SSL in
C1 and is not encryped if I disable SSL. So far, so fine, everything as

But if I set SSL required for the gwia, then communication breaks - "550
TLS negotiation failure". I do not unterstand why SSL/TLS works as long
as it is voluntary and fails as soon as it is mandatory - sounds somehow
human, but does GW work this way?

What do I miss?