Sync via ssh fails when ssl is active

[Johan]

I have computers at two different locations and one computer running 
dovecot at each place. I sync my emails between these two servers using 
ssh and I haven't had any problems with this lately until I upgraded 
dovecot recently.

I now get the following error at location "alfa" when trying to sync 
with dovecot at location "delta"

Jan 20 16:13:09 doveadm: Error: doveconf: Fatal: Error in configuration 
file /etc/dovecot/conf.d/10-ssl.conf line 16: ssl_cert: Can't open file 
/etc/letsencrypt/live/delta.oxyl.net/fullchain.pem: Permission denied

Jan 20 16:13:09 dsync-local(johan at oxyl.net)<FWBVNQN86WH52iQA1AGq6A>: 
Error: read(vmail at 192.168.119.12) failed: EOF (version not received)

Jan 20 16:13:09 dsync-local(johan at oxyl.net)<FWBVNQN86WH52iQA1AGq6A>: 
Error: Remote command returned error 89: ssh -q -p 22 -o 
StrictHostKeyChecking=no -i /datastorage/epost/vmail/.ssh/id_ecdsa 
-lvmail 192.168.119.12 doveadm dsync-server -ujohan at oxyl.net


Trying to sync from "delta" i get the same error but the domain is 
changed in the error-message to 'alfa.oxyl.net'

I can read mail at both locations using STARTTLS. There is no error in 
dovecot.log when I restart the service. If I disable ssl and comment out 
ssl_cert/ssl_key in 10-ssl.conf I have no trouble performing sync 
between servers.

If I run the ssh-command in the error-message as user vmail I get the 
same ssl-error as above.

Any ideas how to solve this?

/Johan Pålsson