How to grant Access -> /var/run/dovecot/stats-writer -> failed: Permission

In logs…

Nov 28 11:22:31 mail postfix/pipe[12443]: C9702DAD01: to=123@mydomain.com, relay=dovecot, delay=0.41, delays=0.22/0.02/0/0.17, dsn=2.0.0, status=sent (delivered via dovecot service (lda(123@mydomain.com): Error: net_connect_unix(/var/run/dovecot/stats-writer) failed: Permission ))