Can't sign into Microsoft 365 Developer Program subscription

Hello Anna_649, Welcome to Microsoft Community. I am a Microsoft user just like you, I hope you are doing well? Sorry for this inconvenience. However, could it be that you have changed the default domain from the issued domain (***.onmicrosoft.com) to a custom domain? If this is correct, I suggest you log in with your account using a custom domain to see if you are able to log in. If this is not the case, with a similar inquiry where the user successfully created a Microsoft 365 E5 sandbox subscription, but when trying to sign in received "This username may be incorrect. Please make sure that the username you typed is correct. Otherwise, please contact the administrator." The solution that worked was to change another account, choose the configurable (second) sandbox when creating the sandbox. https://learn.microsoft.com/office/developer-program/microsoft-365-developer-program-get-started Please let me know if you need more assistance. Give back to the Community, Help the next person who has this issue by indicating if this reply solved your problem. Click Yes or No below. Warm Regards

Hi all,

I am having the same issue here.

I can't sign in to the developer program with the adminstrator username.

Any guide please.

Thanks,

Hello Raymond,

thank you for your response and tips. Unfortunately none of them works for me.

I didnt change a default domain. The error occured right after I set up the subscription.

I also copied and paste the username to make sure it is correct so no typing error.

Also I can not use another account. As I can not use my mobile number twice.

Is there any chance to get support from Microsoft to resolve this issue?

I have the exact same issue. As a test I've set up 2 developer subscriptions: one linked to my Microsoft account that was created two days ago, and one created today linked to my work account using Microsoft Visual Studio Dev Essentials. Both give exactly the same error message when I try to login with the admin account of the sandbox tenant:

This username may be incorrect. Make sure you typed it correctly. Otherwise, contact your admin.

I have tried two different browsers, but this doesn't make any difference.

I'm also having the same issue. Created a Developer subscription and after clicking on "Go to subscription" I input the admin account with the domain (copied and pasted exactly) and get the same error This username may be incorrect. Make sure you typed it correctly. Otherwise, contact your admin.

I tried logging in with the email address I used to create the developer subscription with and there is no Admin Center. Not sure what to do

Same Problem. Is it problem with outlook domain? Or any chance?

Anna_649, I recommend you contact Microsoft business support via telephone to assist you check from their system as it appears to be a growing issue amongst other users. Click link below and select your region to find contact number: https://support.microsoft.com/help/c0389ade-5640-e588-8b0e-28de8afeb3f2 Alternative support channel: https://learn.microsoft.com/microsoft-365/admin/get-help-support

i have the same issue

Phone support is not an alternative. I tried to call then, but after 3 minutes of selecting menu choices, they just told me the URL of online support, and then dropped the call.

Exactly same issue here, 2 days speaking to microsoft without any success.

Although, i`m receiving automatic messages from M365 every 30 minutes saying welcome to my sandbox