I seem to have a problem with a missing link between Microsoft account and Pearson VUE.
See mail below from Pearson VUE:
Dear Kell,
Thank you for contacting Pearson VUE.
We are unable to locate your profile. Your Microsoft account is yet not linked with Pearson VUE, to be able to test you need to have a profile with Pearson VUE. Kindly contact Microsoft directly at http://www.microsoft.com/learning/en-us/help.aspx and they will assist you.
If you need further assistance, please contact us again.
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Regards,
Hana M.
EMEA Support Team