Tag not monitored by Microsoft.
For this type of “An unexpected error occurred during registration. Please try again.” issue when registering for a Microsoft event, the supported path is to contact the official support channel so the account and registration can be checked on the backend.
Use the Microsoft credentials/support help page and open a support request describing the event name, your Microsoft account ID, and that you receive an unexpected error when selecting Register now. The support team can review whether there is an account block, a backend registration problem, or a service issue and then either fix it or complete the registration on your behalf.
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