Corrupted SSL parameters file in state_dir: ssl-parameters.dat

[Terry Jones]

Dovecot 2.2.10
Centos 7
Linux 3.10.0-514.26.2.el7.x86_64 #1 SMP Tue Jul 4 15:04:05 UTC 2017
x86_64 x86_64 x86_64 GNU/Linux

I have been experimenting with backup options to another server using
dovadm and was trying to use the doveadm service as a workaround
seeing as I couldn't decipher what the docs were saying about ssh.

My doveadm stanza looks as follows:

service doveadm {
  inet_listener {
    port = 10101
    ssl = yes
  }
}


If "ssl=no", a pushed "doveadm backup" from the remote machine works OK.

But if I enable SSL, the doveadm backup on the remote machine hangs.
And the destination machine prints the following two massages in the
logs :

Aug  4 17:10:31 bbb dovecot: doveadm: Error: Corrupted SSL parameters
file in state_dir: ssl-parameters.dat - disabling SSL 360
Aug  4 17:10:31 bbb dovecot: doveadm: Error: Couldn't initialize SSL
parameters, disabling SSL


BUT :

(1) /var/lib/dovecot/ssl-parameters.dat  *DOES* exist.
and
(2) If I delete it and restart dovecot, it successully re-creates it, as per
Aug  4 17:02:32 bbb dovecot: ssl-params: Generating SSL parameters
Aug  4 17:06:58 bbb dovecot: ssl-params: SSL parameters regeneration completed