Check you junk email inbox as the temporary password email may have been forwarded there.
Ensure that the nokia.com email addresses are set as safe addresses in your junk email filter. Make sure that this is done for all email accounts associated with your MixRadio account.
If there is uncertainty as to what email account is registered with your MixRadio account, contact Care.
This topic is valid for:
Nokia Lumia 900,Nokia Lumia 800,Nokia Lumia 710