Unable to make SSL connection to mail sever using 3rd-party mail clients

Symptoms

1. Unable to make SSL connection to mail sever using 3rd-party mail clients.

   Windows Security update KB3061518 is installed on client side.

2. Unable to generate dhparams.pem using /usr/share/mkdhparams utility. The following error is shown:

   chown: invalid user: `no'
   

Cause

Software issue with internal ID PPPM-3199 . The fix will be included in further Plesk updates.

Resolution

As workaround, perform these steps:

1. Edit /usr/share/mkdhparams file changing marked strings:

     cp /dev/null /usr/share/dhparams.pem.tmp
     chmod 600 /usr/share/dhparams.pem.tmp
   --> chown root /usr/share/dhparams.pem.tmp
   
     BITS="$DH_BITS"
     if test "openssl" = "openssl"
     then
       if test "$BITS" = ""
       then
           --> BITS=1024
       fi
   

2. Remove existing certificate:

   # rm -f /usr/share/dhparams.pem
   

3. Generate new:

   # /usr/share/mkdhparams
   

4. Restart courier services:

   # service courier-imapd restart
   # service courier-imaps restart