Fatal error: tls_start_servertls() failed

[Mufit Eribol]

Hi All,

I am running cyrus-imapd-2.4.17 on CentOS 7.2.1511 for appx. 20 
mailboxes. I get the following messages every 10-12 days.

imaps TLS negotiation failed: [ip address of a client]
Fatal error: tls_start_servertls() failed

Although cyrus-imapd, saslauthd are still running after this error, 
login credentials are not accepted. As I don't know where the problem 
is, restart the server fixes the problem, well for another 10-12 days.

I would appreciate any hint you may give.

Thanks,
Mufit

Below are the configuration files:

/etc/cyrus.conf:
START {
   recover       cmd="ctl_cyrusdb -r"
   idled         cmd="idled"
}
SERVICES {
#  imap         cmd="imapd" listen="imap" prefork=5
imaplocal     cmd="imapd -C /etc/imapd-local.conf" 
listen="127.0.0.1:imap" prefork=0

   imaps         cmd="imapd -s" listen="imaps" prefork=1
imapslocal    cmd="imapd -C /etc/imapd-local.conf" 
listen="127.0.0.1:imaps" prefork=0

#  pop3         cmd="pop3d" listen="pop3" prefork=3
#  pop3s                cmd="pop3d -s" listen="pop3s" prefork=1
   sieve         cmd="timsieved" listen="sieve" prefork=0
sievelocal      cmd="timsieved -C /etc/imapd-local.conf" 
listen="127.0.0.1:sieve" prefork=0
   # these are only necessary if receiving/exporting usenet via NNTP
#  nntp         cmd="nntpd" listen="nntp" prefork=3
#  nntps                cmd="nntpd -s" listen="nntps" prefork=1

#  lmtp         cmd="lmtpd" listen="lmtp" prefork=0
   lmtpunix      cmd="lmtpd" listen="/var/lib/imap/socket/lmtp" prefork=1

#  notify       cmd="notifyd" listen="/var/lib/imap/socket/notify" 
proto="udp" prefork=1
}
EVENTS {
   checkpoint    cmd="ctl_cyrusdb -c" period=30
   delprune      cmd="cyr_expire -E 3" at=0400
   tlsprune      cmd="tls_prune" at=0400
}

/etc/imapd.conf:
postmaster: postmaster
configdirectory: /var/lib/imap
partition-default: /var/spool/imap
#admins: cyrus
allowanonymouslogin: no
allowplaintext: no
#tls_require_cert: 1
sasl_minimum_layer: 128
servername: mail.wintess.com
autocreatequota: 200000
maxmessagesize: 0
reject8bit: 0
munge8bit: 0
quotawarn: 90
timeout: 30
poptimeout: 10
dracinterval: 0
drachost: localhost
sasl_pwcheck_method: saslauthd
sasl_mech_list: PLAIN
sievedir: /var/lib/imap/sieve
sieve_maxscriptsize: 32
sieve_maxscripts: 5
sieve_allowplaintext: 1
sendmail: /usr/sbin/sendmail
#hashimapspool: true
#defaultdomain: mail
tls_cert_file: /etc/pki/tls/certs/wintess-imap.pem
tls_key_file: /etc/pki/tls/certs/wintess-imap.pem
tls_ca_file: /etc/pki/tls/certs/wintess-imap.pem

/etc/sasl2/smtpd.conf:

pwcheck_method: saslauthd
mech_list: plain login