Gmail gave me a bounce message.
'tuple' object has no attribute 'status_code''
550 5.7.1 Relaying denied
as well as
553 Exception during HTTP GET to '/v4/domains/newsletters.newsblur.com/internal' - 'tuple' object has no attribute 'status_code''
Mailgun, which routes a ton of the internets email, is having a very bad day.
They’ll fix things soon I hope!