I am really baffled by sendmail sending emails to one particular host. It seems absolutely fine while communicating with other servers, but on a particular host it just hangs at the very end:
050 250 local recipient ok 050 >>> DATA 050 354 Command DATA Start mail input; end with <CRLF>.<CRLF> 050 >>> .
The last line is just hanging for 3-4 minutes before continues to
050 250 message sent ok