Users getting locked out did a trace not sure what all this means

We've been having lockout issues on a number of users recently.

I have netlogon debug on my DC and my Cas server.

DC is 2008 R2, CAS is 2010 on 2008 R2

debug log on the DC I see this

03/03 16:04:57 [LOGON] domain: SamLogon: Transitive Interactive logon of (null)\staff from CAS (via DC) Returns 0xC000006A
03/03 16:04:58 [LOGON] domain: SamLogon: Transitive Interactive logon of (null)\staff from CAS (via DC) Entered
[LOGON] domain: SamLogon: Transitive Interactive logon of (null)\staff from CAS (via DC) Returns 0xC000006A

after a few more of these I get this

03/03 16:05:01 [LOGON] domain: SamLogon: Transitive Interactive logon of (null)\staff from CAS (via DC) Entered
[LOGON] domain: SamLogon: Transitive Interactive logon of (null)\staff from CAS (via DC)  Returns 0xC0000234
03/03 16:05:02 [LOGON] 92NDSTY: SamLogon: Transitive Interactive logon of (null)\staff from CAS (via DC) Entered
03/03 16:05:02 [LOGON] domain: SamLogon: Transitive Interactive logon of (null)\staff from CAS (via DC) Returns 0xC0000234

From my cas debug log

03/03 16:04:54 [LOGON] SamLogon: Interactive logon of (null)\staff from CAS Entered
03/03 16:04:54 [CRITICAL] NlPrintRpcDebug: Couldn't get EEInfo for I_NetLogonSamLogonEx: 1761 (may be legitimate for 0xc000006a)
03/03 16:04:54 [LOGON] SamLogon: Interactive logon of (null)\staff from CAS Returns 0xC000006A
03/03 16:04:55 [LOGON] SamLogon: Interactive logon of (null)\staff from CAS Entered
03/03 16:04:55 [CRITICAL] NlPrintRpcDebug: Couldn't get EEInfo for I_NetLogonSamLogonEx: 1761 (may be legitimate for 0xc000006a)
03/03 16:04:55 [LOGON] SamLogon: Interactive logon of (null)\staff from CAS Returns 0xC000006A
03/03 16:05:01 [CRITICAL] NlPrintRpcDebug: Couldn't get EEInfo for I_NetLogonSamLogonEx: 1761 (may be legitimate for 0xc0000234)
03/03 16:05:01 [LOGON] SamLogon: Interactive logon of (null)\staff from CAS Returns 0xC0000234

So based on the debug logs, and If i understand it correctly, it looks like the user tried to check email (via outlook/mobile device) but password was incorrect/wrong and after multiple tries the account got locked.

I checked the account and the computer password was not changed recently. His password did not expire. His phone password was not changed. He was signed in & working on his computer when his account got locked. What he did say was that outlook was open and then suddenly it prompted him to enter a username + password. he ignored it and then his account got locked.

Map drives do not require a password to be entered. IT dept mapped his drive for the user in question.