As seen in OOPS-818B1006, somehow the +contactaddress page of a team with a mailing list tried to set a None email address as the preferred team's email.
The error is: TypeError: Any person's email address must provide the IEmailAddress interface. None doesn't.
Relevant part of the chat I had with barry about this issue:
<matsubara> somehow the mailing_list.address is None
<barry> matsubara: i wonder if that's related to the config fix i'm pushing through pqm now
<matsubara> actually the mailing_list.address could be returning some email and getByEmail() later on returns None.
<matsubara> barry: what's it?
<barry> matsubara: https://pastebin.canonical.com/3634/
<barry> matsubara: i just realized that this might be a more severe problem
<barry> matsubara: if a mailing list was approved using edge's bogus hostname on one machine, and then we try to access that on a different machine, you'll get that None
<barry> and i approved a bunch of new mailing lists this morning
<barry> damn. i'm going to try to put together a query to at least find those bogus email addresses
A fix for this is winding its way through PQM and will get cherrypicked as soon as it lands. We'll need to back-patch the email addresses for about 8 mailing lists that I approved this morning while the bug still existed, but I have a script to do that and we'll apply that soon too.