dovecot - Jul 2021 - dsync I/O Stalled

Hi guys,
i've a strange problem between 2 servers.
It happened after a changing on our network core routing infrastructure.
We've moved to Juniper network and eBGP and iBGP of our server.
One of this server is behind a firewall and communicate with another 
server in another country to sync our emails.
Doveadmin replica seems to be fine, but sometimes i get this error message:

dsync-server(aaaaa at bbb.bb): Error: Timeout during state=sync_mails 
(send=done recv=mails)

It seems like the remote server has troubles to reach our local server 
but if i do a stupid ping i'm not losing anything.

Maybe is there something am i missing?
I thought that it could be related to a MTU problem but i'm not so sure 
and i've increased MTU on the routers involved in routing process 
without success.
I wa missing that both servers are behind a load balancer wich is in our 
local DC.

Can you give me some hints?
Regards,
Paolo


-- 
Paolo Daniele
Intendo s.r.l.                    E-mail: paolo.daniele at intendo.it
Business Unit TLCWEB              Tel.:   +39 0968 430786
Via Coschi, 11                    Skype:  paolo_daniele1
88046 - Lamezia Terme, Cz         Web:    http://www.tlcweb.it
Italia                            Web:    http://www.intendo.it

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Paolo Daniele <paolo.daniele at intendo.it> writes:
> dsync-server(aaaaa at bbb.bb): Error: Timeout during state=sync_mails
(send=done
> recv=mails)
I experience the same errors in my setup.  It seems to happen in intervals
of "replication_full_sync_interval" for me.  Specifically if the
"full
sync" time in the output of "doveadm replicator status
'*'" reaches the
full sync interval time for multiple users.

-- 
Stefan