Sending e-mail with app password don't work

Occasional Visitor

Hello Microsoft Tech Community,

 

I have a customer with problem to sending e-mails via APP password.

 

1. The customer have two step autentication with authenticator

2. On e-mail we made a app password

3. For SMTP we use smtp.office365.com and port 587 TLS

4. The error where sending e-mail: The server committed a protocol violation The server response was: 

 

If I test with my e-mail and app password work fine.

It is any other possibility to test and diagnose the problem ? 

 

1 Reply

Hi @Goran775 ,

 

Microsoft is shutting down legacy authentication. You might want to check if the legacy authentication is already shut down in the clients tenant. 

 

Log in as admin https://admin.microsoft.com > Settings > Org settings > Modern authentication. Make sure basic authentication protocols are selected.

 

Adin_Calkic_0-1650920948988.png

 

Also check settings per user. Go to https://admin.microsoft.com > Users > select user > click on Mail > Manage email apps and make sure you have selected SMTP at least.

 

Adin_Calkic_1-1650921143173.png

 

Also check if you have Conditional Access policy where you blocking legacy authentication.

 

And lastly if Microsoft shut down legacy authentication, you can still opt-out, but eventually you will have to use different smtp service like smtp2go or sendgrid. You can find here on how to opt-out.

 

I hope this helps. Good luck.