The 'Review permissions'/ whichever email that you have used to login to Learn module, the same email account will be used for seeking your approval to sandbox ( as shown in the screenshot below, with a test account).
Do this account work fine outside of Learn modules?
Is this issue confined only to this module or account?
If feasible, you may just use another account which is active, practice and complete the learn modules.
With the Microsoft Learn sandboxes - these are free environments that you can use to explore Azure and other products through Microsoft Learn training modules. The sandbox works independently from your regular subscriptions.
You don't need an Azure account to access sandbox. All you need is a Microsoft account to sign in with.
As mentioned in this FAQ:
What should I do if I lost access to my Learn profile?
Online authentication is the only method to verify ownership of a Learn profile. If you have lost access to the account associated with your Learn profile and no longer have access to your Learn profile, you will have to recover the authentication account through its recovery process to regain access to your Learn profile. To avoid this situation, if you only have a work/school account linked to your Learn profile, consider also linking your personal account to your Learn profile. You can "Add account" on the Learn profile settings page. Note that Microsoft Learn will not manage Learn profiles on behalf of users.
Also, review the FAQ: How do I activate the sandbox?