Invalid Email Address Issue

[Kyle_Lampis]

I have a contact with an email address that Marketo claims is invalid, yet when I reached out to the user, they claim that this address is in fact valid and operational.

This is the error message I receive for 'Email Invalid': 

554 delivery error: dd This user doesn't have a rocketmail.com account (REDACTED@rocketmail.com) [0] - mta4372.mail.bf1.yahoo.com

Can anyone assist me in solving this?

[SanfordWhiteman]

Nothing obligates a server to give an accurate SMTP error code. So, if the mailbox otherwise is operational, they've blocked emails from Marketo even if the message doesn't literally say "no likey Marketo".

[Kyle_Lampis]

Thanks for your response. Do you think it has anything to do with the Rocketmail domain? This is not very commonly used amongst our database.

[SanfordWhiteman]

You could create a sample Rocketmail account and see if it's global. It could just as easily be local to this mailbox, though.