Did you fill in the SMTP address, SMTP username, and SMTP password fields correctly, as specified by Mandrill?
Yes (for Mailjet).
Make sure you copy and paste the Mandrill password – do not type it in manually.
I did do this (with MailJet).
Does the value for DISCOURSE_DEVELOPER_EMAILS correctly have one set of single quotes around it ‘like this’?
Yes
Are the values aligned with the correct indentation for the email section? YML files are alignment sensitive. Even one extra space at the beginning of a line will cause problems.
I believe so, I didn’t change the alignment that was there.
Did you remove the YML comment marker # in front of the lines?
Yes
Is Digital Ocean blocking your email?
I don’t use Digital Ocean, so no.
And Linode is fine with email that isn’t spam.
Is Mandrill blocking your email?
I use MailJet so no, also because I could use the expample python script to send email, I know they aren’t blocking email.
Did you properly set up DKIM and SPF records for your domain?
Yes I did.