QQ Mail SMTP Error 550: Fixing 'The From header is missing or invalid' in Python
When using QQ Mail's SMTP server to send emails via Python's smtplib, you may encounter the error:
(550, b'The "From" header is missing or invalid. Please follow RFC5322, RFC2047, RFC822 standard protocol. https://service.mail.qq.com/detail/124/995.')
This typically happens when the From header in the email is incorrectly encoded.
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Posted on Thu, 28 May 2026 17:43:18 +0000 by .evo.