Hello Zara Dezfuli,
Thanks for your question.
For the phone number issue, can you try signing up on your mobile. That work around has resolved for some users.
Per the sandbox issue: This usually happens if If your account is associated with another tenant (e.g., your company’s), the sandbox environment can’t grant access. Personal accounts often resolve this automatically
Try the following:
- Completely sign out of the Microsoft Learn portal, Azure portal, and any other Microsoft services in your browser.
Use an InPrivate/Incognito browser window to avoid cached credentials.
- Sign back in with your Microsoft Learn account (the one you’re using for training).
- Ensure you’re using a personal Microsoft Account (e.g., @outlook.com, @hotmail.com, etc.) and not a work/school account.
- Old cached credentials or tokens might interfere. Clear your browser’s cache and cookies for microsoft.com, azure.com, and learn.microsoft.com.
- Sometimes browser extensions or settings block access. Test with Edge, Chrome, or Firefox.
You can mark it 'Accept Answer' and 'Upvote' if this helped you
Regards,
Abiola