We are network edition and having the same problem as described here. Continuing to work with support but no luck so far. Not able to send mail with TLS or SSL, but can POP with SSL fine. Mailman server also cannot connect to Zimbra with same "lost TLS" issue. Using Thawte commercial certificate and supplied CA root cert file, also have followed this article about "too many files":
Error (MTA): Unable to set STARTTLS - Zimbra :: Wiki
Continue to see this error:
Aug 3 04:07:19 mail postfix/smtpd[3038]: warning: network_biopair_interop: error writing 8192 bytes to the network: Connection reset by peer
Aug 3 04:07:19 mail postfix/smtpd[3038]: SSL_accept error from localhost.localdomain[127.0.0.1]: -1
Aug 3 04:07:19 mail postfix/smtpd[3038]: lost connection after STARTTLS from localhost.localdomain[127.0.0.1]
Suspect that we have same issue as this post:
TLS-Connection - Broken Pipe network_biopair_interop
Anyone having any luck?