ARTICLE AD BOX
I’m experiencing an issue in production where login and signup fail due to an SMTP authentication error when using Django Allauth.
❗ Error
SMTPAuthenticationError: (535, b'Incorrect authentication data')Relevant traceback:
File ".../django/core/mail/backends/smtp.py", line 97, in open self.connection.login(self.username, self.password) File ".../smtplib.py", line 669, in auth raise SMTPAuthenticationError(code, resp)Environment
Django: 6.0.3
Python: 3.14.3
django-allauth: latest
Deployment: cPanel (Passenger)
OS: Linux (RHEL-based)
Email Configuration
EMAIL_BACKEND = 'django.core.mail.backends.smtp.EmailBackend' EMAIL_HOST = 'mail.agrotekpluss.com' EMAIL_PORT = 587 EMAIL_USE_TLS = True EMAIL_USE_SSL = False EMAIL_HOST_USER = config('EMAIL_HOST_USER') EMAIL_HOST_PASSWORD = config('EMAIL_HOST_PASSWORD') DEFAULT_FROM_EMAIL = '[email protected]'Allauth Settings
ACCOUNT_EMAIL_VERIFICATION = "mandatory" ACCOUNT_LOGIN_METHODS = {'email'} ACCOUNT_SIGNUP_FIELDS = ['email*', 'password1*', 'password2*']Steps to Reproduce
Go to /accounts/login/ or signup page
Submit valid credentials
Allauth attempts to send verification email
Request fails with SMTPAuthenticationError
Actual Behavior
Login/signup fails
Email is not sent
Exception is raised during SMTP authentication
Expected Behavior
User logs in or signs up successfully
Verification email is sent
What I’ve Observed
The issue only happens in production
It occurs specifically when Allauth sends a verification email
If I disable email verification, login works:
ACCOUNT_EMAIL_VERIFICATION = "optional"Question
What could cause (535, b'Incorrect authentication data') in this setup?
Could it be incorrect SMTP credentials or host mismatch?
Does the SMTP server need additional configuration for TLS/auth?
Are there known issues with Django 6 / Python 3.14 and SMTP?
Additional Notes
SMTP is configured on port 587 with TLS
Using environment variables for credentials
No issues locally (only in production)
Any guidance on debugging or fixing SMTP authentication in this context would be appreciated.
