Event ID - 4183

Event Id4183
SourceMSExchangeIMC
DescriptionAuthentication attempt (AUTH LOGIN) from hostname as ntdomain\userid failed: LogonUser() call failed with error: Logon failure: unknown user name or bad password
Event InformationAccording to Microsoft:
Cause:

You have entered incorrect logon credentials AND you have the client configured to send credentials for the outgoing mail server.
Resolution:
If the Exchange servers IMS does not require authentication from the hosts or clients that connect to it, the client does not need to be configured to require authentication. To check if the IMS requires authentication:
1. Use the Exchange Server Administrator to open the IMS properties.
2. Click the Connections tab.
3. Inspect the Accept Connections area:
If From any host (secure or non-secure) is selected,
the client doesnt need to be configured to required authentication on the outgoing mail server.
If Only from hosts using Authentication is selected,
the client does need to be configured to required authentication on the outgoing mail server.
To check how the Outlook Express client is configured, click Accounts on the OE Tools menu. Select the mail account and click Properties / Servers tab / Outgoing Mail Server area:
If IMS requires authentication,
check the My server requires authentication box.
Click Settings and enter the proper logon information.
If IMS doesnt require authentication,
do NOT check the My server requires authentication box."

If you use incorrect logon credentials on a Post Office Protocol version 3 (POP3) or Internet Message Access Protocol, Version 4rev1 (IMAP4) client (when connecting to a Microsoft Exchange Server Internet Mail Service or Exchange 2000 Server SMTP connector to send outgoing SMTP mail) that is configured to enter authentication credentials for the outgoing mail server, you may receive this error message.
MORE INFORMATION :
When you enter the logon credentials at the client, use the correct user name and password, or configure the client so that the outgoing mail server does not require authentication. 
For more information check Microsoft article given b
Reference Links

Event 4183, POP3 or IMAP4 client cant send SMTP mail.

POP3 or IMAP4 Client Cannot Send SMTP Mail

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