Maileater_nxd.log shows logs similar to:
ERROR [ForkJoinPool-1-worker-0] c.c.S.m.c.JavaMailIMAPClient - Failed to connect to the Store.
javax.mail.AuthenticationFailedException: AUTHENTICATE failed.
at com.sun.mail.imap.IMAPStore.protocolConnect(IMAPStore.java:725)
at javax.mail.Service.connect(Service.java:366)
at javax.mail.Service.connect(Service.java:246)
at com.ca.ServicePlus.mail.connection.JavaMailIMAPClient.connectToStore(JavaMailIMAPClient.java:147)
at com.ca.ServicePlus.mail.connection.JavaMailIMAPClient.initializeClient(JavaMailIMAPClient.java:135)
at com.ca.ServicePlus.maileater.ConnectSession.Hunny_Connect(ConnectSession.java:260)
at com.ca.ServicePlus.maileater.ConnectSession.Connect(ConnectSession.java:156)
at com.ca.ServicePlus.maileater.ConnectSession.check_mail(ConnectSession.java:178)
at com.ca.ServicePlus.maileater.IMAP4EmailClient.check_mail(IMAP4EmailClient.java:138)
at com.ca.ServicePlus.maileater.Mailbox.lambda$new$1(Mailbox.java:822)
at java.util.concurrent.ForkJoinTask$AdaptedCallable.exec(Unknown Source)
at java.util.concurrent.ForkJoinTask.doExec(Unknown Source)
at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(Unknown Source)
at java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)
at java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source)
TRACE [ForkJoinPool-1-worker-0] c.c.S.m.ConnectSession - [mailbox:MAILBOXNAME:400979] Failed to connect to IMAP4 server outlook.com at port 993
This is generic and doesn't give us very much information.
Reference Failed to Connect to the Store Error, AUTHENTICATE failed error in maileater_nxd Logs when using an Office365 account to ensure the configuration is correct.
Then look in Azure logs under Azure Active Directory > Monitoring > Sign-ins
Look for email box user name and Application "Office 365 Exchange Online"
Release : 17.x
Component : Svc Desk Email
Mailbox in Microsoft365
Conditional Access Policy is misconfigured or not configured at all
Sign-ins log shows:
Status: Failure
Failure Reason: Access has been blocked by Conditional Access policies. The access policy does not allow token issuance.
Mailboxes were not authenticating because there was no Conditional Access Policy created in Azure.
Have customers Azure Team Create an appropriate Conditional Access Policy for the mail user account under: