If you want to use your Microsoft 365 account to issue restores then you need to apply ApplicationImpersonation role for either a group or specific user.

Below we are doing it using a group. 

Go to the following website https://admin.exchange.microsoft.com/

Click on Roles followed by click on Admin roles

Click Add role group

Give the new role a name “365 backup Admin”

Add the ApplicationImpersonation role/set the checkmark.

Assign users to the group, in this case we choose a user named Harvey.

Finish the new group and wait for the changes to take place.

You have now completed setup of the impersonation role, with this role the selected users are now able to restore exchange data from the restore portal.