Exchange internal emails sometimes cannot be successfully sent

Question

The company used the Exchange2019 server, established in the local computer room, without using cloud email, and sent and received emails through Outlook 2016. Sometimes users feedback that sending multiple emails to internal users may result in a return message stating that the delivery of the email to the following recipients or groups failed:

Kevin_ Wang

There is a problem with the recipient's email. Please try sending the email again. If the problem persists, please contact your email administrator.

The following organization has rejected your email: EX2019-1.sgssemi.com.

Answer 1

Hello Ming

Try removing the autocomplete list and manually entering the recipient's email address to see if that produces any different results.

Also, if you are an administrator, try viewing the message delivery report in the Exchange admin center for more information about message delivery issues.

Please check this： https://learn.microsoft.com/en-us/exchange/mail-flow/non-delivery-reports-and-bounce-messages/non-delivery-reports-and-bounce-messages?view=exchserver-2019

Regards

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