Recent Issues with Isilon & AD

Hello, everyone,

After some updates to our AD DCs over the weekend, our Isilon is failing to authenticate, but only when it negotiates to Kerberos authentication. If it negotiates down to NTLM, it works fine, but Kerberos does not work. I've done all of the usual - verified SPNs and such - but no luck.

In /var/log/lsassd.log, I'm seeing the following messages repeated quite frequently:

2022-11-29T12:32:02-05:00 <30.3> ISILON-2(id2) lsass[33831]: [lsass] Failed to authenticate user (name = 'Chuck_Norris') -> error = 40134, symbol = LW_ERROR_RPC_ERROR, client pid = 4294967295
2022-11-29T12:32:02-05:00 <30.3> ISILON-2(id2) lsass[33831]: [lsass] AD_NetrlogonOpenSchannel(dc1.example.com) failed with 3221225473 (0xc0000001) (symbol: 'STATUS_UNSUCCESSFUL')
2022-11-29T12:32:02-05:00 <30.4> ISILON-2(id2) lsass[33831]: [lsass] Failed to get Ntlm Target Info Type Error code: 40134 (symbol: (null))
2022-11-29T12:32:03-05:00 <30.3> ISILON-2(id2) lsass[33831]: [lsass] AD_NetrlogonOpenSchannel(dc1.example.com) failed with 3221225473 (0xc0000001) (symbol: 'STATUS_UNSUCCESSFUL')
2022-11-29T12:32:03-05:00 <30.3> ISILON-2(id2) lsass[33831]: [lsass] Failed to authenticate user (name = 'Chuck_Norris') -> error = 40134, symbol = LW_ERROR_RPC_ERROR, client pid = 4294967295

 Any hints would be greatly appreciated.