If there are no emails sent from ProtonMail addresses in your inbox, it could be due to either the setting configurations done by the sender of the email, the provider of the email, or the spam filters. Start by requesting the sender to verify and ensure that the email is sent. Ask them to check the contact address and their sent folder for any mistakes.
For example, some services say, “Don’t include ProtonMail domains in the list for my email service.” Other services might mistakenly mark it as spam, and not all of these services are reliable. Therefore, it is prudent that you check junk and spam folders for these emails as well and flag them as “Not Spam” if you do find such emails.
However, do check your outbox for coding errors as well. Also, ensure that you are not decluttering ProtonMail by setting out rules for all spam. Finally, check with your email service provider to confirm that there are no issues on their end with the delivery of ProtonMail, or the service might be subverted entirely.
In case the issue continues, we will suggest both the ProtonMail sender and you reach out to the ProtonMail Customer Support team for better assistance. It is advisable that you look into the situation quickly so various gaps in email communication and coordination do not take place.
