Error<53761>-Plugins-conn=-1 op=-1 msgid=-1-connection Bind through PTA failed (91). Retrying ...

LDAP6.3 starts the instance in the DSCC console, but the operation status displays "Unexpected error" and the log reads as follows:

04/may/2016:21:10:39 +0800]-Sun-java (tm)-system-directory/6.3 B2008.0311.0224 (32-bit) starting up
[04/may/2016:21:10:39 +0800]-Listening on all interfaces port 11111 for LDAP requests
[04/may/2016:21:10:39 +0800]-Listening on all interfaces ports 11112 for LDAPS requests
[04/may/2016:21:10:39 +0800]-SLAPD started.
[04/may/2016:21:10:39 +0800]-info:0 entries in the directory database.
[04/may/2016:21:10:39 +0800]-info:add:0, modify:0, modrdn:0, search:0, delete:0, compare:0, bind:0 since startup.
[04/may/2016:21:10:40 +0800]-error<53761>-plugins-conn=-1 op=-1 msgid=-1-connection Bind through PTA failed (retrying).
[04/may/2016:21:10:40 +0800]-error<53761>-plugins-conn=-1 op=-1 msgid=-1-connection Bind through PTA failed (91).
[04/may/2016:21:10:40 +0800]-error<53761>-plugins-conn=-1 op=-1 msgid=-1-connection Bind through PTA failed (retrying).
[04/may/2016:21:10:40 +0800]-error<53761>-plugins-conn=-1 op=-1 msgid=-1-connection Bind through PTA failed (91).

Check that the/etc/hosts configuration file was found to be incorrect, 127.0.0.1 and:: 1 after the hostname written to the host name of the other server. Because the/etc/hosts configuration file is copied and pasted directly from other servers, it is wrong. Modify to correct, delete the original instance and recreate it after normal.

# don't remove the following line, or various programs
# that require network functionality would fail.
127.0.0.1 testldap210.com testldap210
:: 1 testldap210.com testldap210
......

Reference: https://community.oracle.com/thread/2013701

Error<53761>-Plugins-conn=-1 op=-1 msgid=-1-connection Bind through PTA failed (91). Retrying ...