Hi @Alan Mathison,
Note: Kindly do not share any PII data (e.g email ID) on the public forum for your privacy and security.
As we understand from your post, you are unable to sign into Microsoft Learn Sandbox.
Make sure that you check whether your organization account has access associated with your Learn profile. Else you can create a new, learn profile using the different account as your certification profile as mentioned in the doc: https://learn.microsoft.com/en-us/azure/education-hub/azure-dev-tools-teaching/troubleshoot-login
Please follow the below steps:
1.If you already have one or more work or school (AAD) accounts associated with your Learn profile.
2.Sign in to Learn using a work or school (AAD) account.
3.Go to the “settings” page in your Learn profile.
4.Under the “Account management” section, remove your current personal account (MSA).
5.Select “Add account” and sign in with the personal account (MSA) that you use for your Certification Profile.
6.Sign into Microsoft Learn with your newly added personal account (MSA).
7.Complete the certification profile connection process.
If the issue persists still, please follow the troubleshooting steps below, to rule out browser-related issues:
1.Log out from all Microsoft accounts in your browser and try signing in with your Learn id.
OR
2.Try to login to your Learn account in a new incognito window or new private window.
We hope this information proves helpful. If you require further assistance, please don't hesitate to reach out.
Thank you for helping to improve Microsoft Q&A!