Open Directory Problems, users intermittently failing to authenticate

Hello,

I have an OD Master and OD replica. These servers are also the DNS Secondary and DNS primary. Users connecting to them can authenticate around half the time successfully, and half the time they cannot, and get the following error:

4/10/15 2:31:06.870 PM authorizationhost[324]: Failed to authenticate user <username> (error: 9).

When I look at the binding in users and groups, it still shows a green light. If I rebind and reboot, the issue is often (but not always) immediately resolved.

I thought it might've been some sort of DNS issue, but everything looks fine on the OD Master, and I can resolve the dns name fine on the clients. This issue also even occurs if I bind users directly to the IP address.

I also see this error on the server often repeated, but I'm not sure that it is related.

4/10/15 2:40:59.949 PM slapd[2132]: GSSAPI Error: The context has expire (Success)

Any thoughts on what could be going on?

Thank you,

CJ