What version are you running?
4.0.4
What's the URL of the page containing the problem?
It's the email notifications
What steps will reproduce the problem?

As an admin change a users email address to blank
Do something that'll send a notification email
Never receive mail
Cry
Look at logs see it failed to parse
Disable sending email for that user

What is the expected output? What do you see instead?
The user should be silently ignore
What operating system are you using? What browser?
Linux chrome/firefox
Please provide any additional information below.
Users are ending up with no email address because I have a custom auth provider that syncs during login to an SSO (JetBrains Hub) which allows users to remove their email address.
I will be patching the custom auth provider to fail their logins with no email, but figured this might bite someone else as well.