LDAP replication issue

I have two LDAP on Linux (RHEL) nodes clustered as peers, there is something wrong in the replication, need to troubleshoot and solve it

62a613e3 do_syncrepl: rid=001 rc -1 retrying
62a6141f do_syncrep2: rid=001 got search entry without Sync State control (dc=xyz,dc=com)
62a6141f do_syncrepl: rid=001 rc -1 retrying (11 retries left)
62a6154b do_syncrep2: rid=001 got search entry without Sync State control (dc=xyz,dc=com)
62a6154b do_syncrepl: rid=001 rc -1 retrying (10 retries left)
62a615ef connection_read(32): no connection!
62a61c91 do_syncrepl: rid=001 rc -1 retrying (9 retries left)