Zimbra Access denied. Proxy unable to reach user mailbox server

[sunucupark]

Hi Everyone,

We are using Zimbra with some proxy node, some mailbox, mta nodes with z-push.

We have a problem,

Sometimes our some users can not see your folder on webmail and some user get authentication error with activesync.

and i want to note that,

when we change webmail ajax to html mode folder was seen,

and we have some logs.

08/11/2021 13:39:01 [10286] [ERROR] [user@xx] Zimbra->SoapRequest(): SOAP FAULT: Error Code [account.AUTH_FAILED]
08/11/2021 13:39:01 [10286] [ERROR] [user@xx] Zimbra->SoapRequest(): SOAP FAULT: Error Reason [authentication failed for [user@xx]]
08/11/2021 13:39:01 [10286] [ERROR] [user@xx] Zimbra->Logon(): END Logon - Proxy Error { connected = false }
08/11/2021 13:39:01 [10286] [ERROR] [user@xx Zimbra->SoapRequest(): SOAP FAULT: Error Reason [authentication failed for [user@xx]]
08/11/2021 13:39:01 [10286] [ERROR] [user@xxr] Zimbra->Logon(): END Logon - Proxy Error { connected = false }
08/11/2021 13:39:01 [10286] [FATAL] [user@xx] Exception: (ServiceUnavailableException) - Access denied. Proxy unable to reach user mailbox server
08/11/2021 13:39:01 [10286] [FATAL] [user@xx] Exception: (ServiceUnavailableException) - Access denied. Proxy unable to reach user mailbox server
08/11/2021 13:39:03 [26781] [ERROR] [user@axx] Zimbra->SoapRequest(): SOAP FAULT: Error Code [account.AUTH_FAILED]
08/11/2021 13:39:03 [26781] [ERROR] [user@xxr] Zimbra->SoapRequest(): SOAP FAULT: Error Code [account.AUTH_FAILED]


What are you thinking about this problem?

How can we resolve this?

Regards,

[sunucupark]

We have 50 clients but only 3 clientss have this problem, If have any thing, please advice to us,

Thanks