Windows Server 2025 standard activation by phone failed

Question

Windows Server 2025 standard activation by phone failed

SVATUNEK, Anton 0

Dear Support,

i have an isolated OT environment where i had to install a new windows server 2025 standard.

the Windows License is a ROK license from HPE.

as i did not have a DVD-drive i downloaded the evaluation version and converted it after the installation to a standard version.

then the slmgr.vbs /ipk thing

and slui.exe 4

received a phone number and an installation ID => switched to https://aka.ms/aoh

filled out all fields and received a confirmation ID

=> typed this ID in my win2025 machine and =>

=> Can't activate windows by phone - contact your administrator

any suggestions what to do?

i did this phone stuff since win2012r2 and it worked always. this is my first 2025 machine

br

Anton

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5 answers

Your answer

Answer 1

SVATUNEK, Anton 0

double checked the installation ID and the confirmation ID.

error message on the isolated system: can't activate by phone.

connection to the internet is NOT AN OPTION

Reinder Gerritsen 0 Reputation points

2026-09-03T08:55:44.1433333+00:00
The solution - at least, it worked for me:

On the terminal, first use

slmgr.vbs /dti

this will return your installation id (but without spaces)

Then when aka.ms/aoh returns your activation code run:

slmgr.vbs /atp <codestring>

Where the codestring is again without spaces. this is exactly the same code, but where the UI fails, commandline just activates successfully

Answer 2

DustinTran 600 Moderator

Hi Anton.

Thank you for contacting to Microsoft Community.

As far as i know, Windows Server 2025 phone activation may fail because Microsoft is phasing out traditional telephone activation, moving services online as of late 2025.

You can review the following steps bellow to check the issue.

Use CMD Activation:

Run Command Prompt as Administrator:

slmgr.vbs /ipk <Your-Product-Key> (to install key).

slmgr.vbs /ato (to force online activation).

Registry Check:

If slui 4 is completely broken, check

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SoftwareProtectionPlatform\Activation

for DisablePhone and set it to 0.

In case you need urgent support or quick help, you can reach out to License Support for further assistance.

If you found this answer helpful, please click "Accept Answer" to support our community and others.

Thank you again for your patience and support!

Dustin Tran

Reinder Gerritsen 0 Reputation points

2026-09-03T08:41:01.3666667+00:00

Hi Dustin, whilst intentions are obviously good, your suggestion to use slmgr.vbs /ato is very much not appropriate for the situation. This command requires a direct internet connection. As the OG clearly stated, Offline Activation is essential as he has the machine in an Operational Technology (or Process Automation) Industrial network.

By a very elementary security design, OT networks should not in any circumstance be technically capable to access any internet resource

As the OG also mentioned, the Activation Phoneline redirects you to the website aka.ms/aoh where you may enter the Installation ID and receive the Activation code.

I just did the same thing, and I receive the same error. The code returned by the online portal seems to be incorrect, but it does not tell why it failed just to contact the system administrator for more info. Not very helpfull.

Sad to see Microsoft did not anticipate this very well in their hunt for "Everything online".

Answer 3

SVATUNEK, Anton 0

there are NO ERROR CODES

it is just saying "can't activate windows by phone"

give me an alternative to activate my windows without internet connection

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Answer 4

SVATUNEK, Anton 0

i want to talk or type to a natural person!

0 comments

Answer 5

It seems you're experiencing an issue with activating Windows Server 2025 Standard by phone after converting from an evaluation version. Here are a few suggestions to troubleshoot this problem:

Verify the Installation ID: Ensure that the Installation ID you received is entered correctly when prompted for the confirmation ID. Any mistakes in this number can lead to activation failures.
Check for Connectivity Issues: Since you are in an isolated OT environment, ensure that your server can reach the necessary Microsoft activation servers if applicable. If it's completely isolated, you may need to ensure that the activation process is supported in your environment.
Use the Correct Product Key: Make sure that the product key you are using is indeed a valid ROK license from HPE for Windows Server 2025. If there are any discrepancies with the key, it could prevent activation.
Contact Microsoft Support: If the issue persists, consider reaching out to Microsoft support for assistance. They can provide specific guidance or resolve issues related to your ROK license and activation process.
Try Online Activation: If possible, try to activate online instead of by phone, as this may bypass some of the issues you are encountering with the phone activation process.
Review Activation Error Codes: If you receive any specific error codes during the activation process, refer to Microsoft's documentation on activation error codes for more detailed troubleshooting steps.

These steps should help you in resolving the activation issue.

References: