If you are a proton mail user first check your spam / junk email folder for the missing messages. If the messages still cannot be locate we recommended adding the email do-not-reply@oann.com to you proton mail whitelist and then attempt the account activation or password reset procedure again so the system resends the needed activation or password reset emails.
Instructions from proton mail can be found here on how to add do-not-reply@oann.com to your email accounts whitelist.
Spam filtering, Allow Lists, and Block Lists (protonmail.com)