I’m having trouble setting up my Outlook email connection in n8n and keep getting authentication errors. I’ve already done the basic setup steps like turning on IMAP/POP access in my Outlook settings and setting up two-factor authentication with an app password.
But I keep getting this error message: “Couldn’t connect with these settings Invalid login: 535 5.7.139 Authentication unsuccessful, basic authentication is disabled.”
I’m wondering if there’s something else I need to enable in my Outlook account to make SMTP work properly. Has anyone else run into this problem? What am I missing here?
yep, i had that too. basic auth is disabled by default now. look in the admin settings, you could re-enable it for smtp. if still no luck, consider switching to OAuth2. that solved my probs!
Had this exact same problem migrating to n8n last month. Microsoft changed their security policies and now blocks basic auth for SMTP by default. Even if your app passwords are set up right, it’ll still fail unless you turn on basic auth for SMTP in your tenant settings. If you’ve got admin access to Office 365, go to Exchange admin center and find authentication policies. Enable basic auth for the SMTP AUTH protocol specifically. Don’t have admin access or using personal Outlook? Switch to OAuth2 in n8n instead of SMTP credentials. It gets around the basic auth block and it’s more secure anyway.
This error got super common after Microsoft tightened security. I fixed it by checking which authentication method my Exchange Online was actually using. Had app passwords set up right, but turns out my org disabled authenticated SMTP entirely through conditional access policies. Check if you’re caught under security policies that override basic SMTP settings. Also see if your Outlook’s tied to an organization or school - they usually lock down SMTP auth no matter what your personal settings say. If you’re stuck with SMTP and can’t do OAuth2, try making a dedicated service account just for n8n. Sometimes those have different auth rules than regular accounts.
Microsoft’s stricter auth requirements catch tons of users off guard. I hit this same issue setting up email automation for a client. Your config isn’t the problem - Microsoft now forces modern auth by default. What worked for me was ditching SMTP entirely and switching to Microsoft Graph API. You can still use n8n, but you’ll need to create an app registration in Azure AD and use the HTTP Request node to send emails through Graph API endpoints. It’s more setup upfront, but it sidesteps all the SMTP auth headaches and gives you better error handling. Plus you won’t get burned by Microsoft’s constant auth changes.
had the same issue last week. microsoft’s disabled basic auth for most tenants now. check if your org admin blocked it completely - that’s usually what causes this. if you can’t get oauth working, try using graph api instead of smtp.
sounds like microsoft’s security defaults are blocking ya. i hit this exact issue too - even with app passwords right, outlook kept rejecting smtp connections. check if ‘less secure app access’ is disabled at the account level, not just the imap/pop settings ya already tweaked.
Microsoft pushed these auth restrictions to most tenants in 2023 - that’s why your SMTP setup broke overnight even with app passwords working before. Hit the same wall when I moved workflows to n8n earlier this year. Your config’s fine, it’s just Microsoft forcing modern auth now. Try this: check if your Outlook account has ‘per-app passwords’ for SMTP instead of generic app passwords. Some accounts treat these differently. Go to your Microsoft account security settings and generate an application-specific password where you can pick SMTP as the service. If that doesn’t work, swap to Gmail temporarily while testing your n8n workflows - their app passwords still work great with SMTP. Gets you back up and running while you figure out OAuth2 or Graph API later.