Solved: Unable to activate Windows server 2016 though GUI. getting error "This Edition Cannot Be Upgraded"

Issue:

1:

Windows server 2016 was rebooting again and again

2:

Unable to activate Windows server 2016 "Microsoft Windows Server 2016 Standard Evaluation" Edition, though GUI to Standard edition. getting error "This Edition Cannot Be Upgraded"

Solution:

Dism /online /Set-Edition:ServerStandard /AcceptEula /ProductKey:12345-qwert-asdfg-zxcvb-qazws

Other findings:

1. The server was running in VMWare environment.
2. The server was rebooting again and again.
3. After looking into the event viewer for the reboot cause found the error "The kernel power manager has initiated a shutdown transition.  Shutdown Reason: Kernel API"
4. The Dism /online set-edition:serverstand.... command took more than 30 minutes to complete
5. The server rebooted more than one time after running the DISM command.
6. the cleaning up process took few hours to complete

Resolved: [{LED=451 4.4.395 Target host responded with error. -> 421 4.4.1 Connection timed

 Mails stuck in queue, with the following error in queue.

[{LED=451 4.4.395 Target host responded with error. -> 421 4.4.1 Connection timed

the solution was:

Enable-ExchangeCertificate -ThumbPrint "thumbprint of the required new certificate" -services SMTP

Detail:

After updating SSL certificate in Exchange Server 2016 environment, including mailbox servers and edge servers, the mails were getting stuck in queue with the error "[{LED=451 4.4.395 Target host responded with error. -> 421 4.4.1 Connection timed"

after looking into it further, it was found that the new certificate was not enabled for the SMTP service.

So by enabling the new Certificate for the SMTP service, the issue was resolved.

Enable-ExchangeCertificate -ThumbPrint "thumbprint of the required new certificate" -services SMTP