I'm having some problems with QMail under Plesk8.1
Some mails from certain providers are delayed because of problems with TLS.
From logging of the other providers, I see that the problem is caused by TLS:

Jan 18 12:55:42 provider1 sendmail[8549]: m0IBrgoB008537: to=<info@host.tld>, delay=00:02:00, xdelay=00:02:00, mailer=esmtp, pri=120529, relay=mail.host.tld. [xxx.xxx.xxx.xxx], dsn=4.0.0, stat=Deferred: 403 4.7.0 TLS handshake failed.
Jan 18 14:04:18 provider1 sendmail[10984]: m0IBrgoB008537: to=<info@host.tld>, delay=01:10:36, xdelay=00:00:03, mailer=esmtp, pri=210529, relay=mail.host.tld. [xxx.xxx.xxx.xxx], dsn=2.0.0, stat=Sent (ok 1200661208 qp 28544)

So my first guess was to disable TLS on my server, but there is almost no information about disabling TLS and when I search SWSoft on TLS, it finds nothing.
BTW: Why does sending works the second time? Did the server at provider1 disable TLS the second time?

I hope that someone can help me with this. Eighter by disabling TLS or by any other solution.

Below the banner of my mailserver.
[root ~]# telnet localhost 25
Connected to localhost.localdomain (
Escape character is '^]'.
220 <mailserver> ESMTP
ehlo localhost