Send Mail Error: "[System.NotSupportedException] No compatible authentication mechanisms found." (4322768)

The attempt to send an email via SMTP results in the following error message:

"[System.NotSupportedException] No compatible authentication mechanisms found.
at VI.JobService.ProcessorThread._ExecuteJob(Job job, JobResult result)
at VI.JobService.JobComponents.MailComponent.Activate(String task)
at VI.JobService.JobComponents.MailComponent._SendRichMail()
at VI.JobService.JobComponents.MailComponent._Send(MimeMessage message, MailSecurity security)
at VI.JobService.JobComponents.MailComponent._GetOrOpenSmtpConnection()
at MailKit.Net.Smtp.SmtpClient.Authenticate(Encoding encoding, ICredentials credentials, CancellationToken cancellationToken)"

Or

"Server supported authentication mechanisms: GSSAPI, NTLM, LOGIN"

A possible reason for this error message might be that NTLM is activated on the mail server.

Identity Manger uses the Open Source libraries "MailKit" for mail dispatch.  These support the following standards currently:

"SCRAM-SHA-256",

"SCRAM-SHA-1",

"CRAM-MD5",

"DIGEST-MD5",

"PLAIN",

"LOGIN"

Older versions of MailKit supported NTLM, but this support has been removed as of July 2017.

WORKAROUND

Use one of the supported authentication mechanisms on the mail server.

STATUS

The One Identity Manager product team will evaluate the request and this feature may become available in a future release.