B4J Question SMTP response 421 received. Server closed connection.

[Angelo Messina]

hi all, with B4J is it possible to send simple email alerts only to one user?
i tried with the net library, but it doesn't send anything
it always comes back to me
org.apache.commons.net.smtp.SMTPConnectionClosedException: SMTP response 421 received. Server closed connection.

 

[EnriqueGonzalez]

Yes it is possible and quite simple, you might have an error in your SMTP configuration, better to share some code hiding the sensitive information.

 

[Angelo Messina]

I copied the source of Erel as it was, I added user and password and Gmail.com

 

[EnriqueGonzalez]

I copied the source of Erel as it was, I added user and password and Gmail.com

For gmail you need to add 3rd party apps to be able to access.

Less secure apps & your Google Account - Google Account Help

Starting January 2025, less secure apps, third-party apps, or devices that have you sign in with only your username and password will no longer be supported for Google Workspace accounts. For exact

support.google.com

they actually give you an extra code that you will use as the password

 

[Angelo Messina]

can you tell me what they are?

 

[EnriqueGonzalez]

Just follow the steps
Another guide:

How to enable less secure apps to access gmail accounts

Enabling less secure apps to access accounts

hotter.io

If you are stuck send us screen shots

 

[MathiasM]

I copied the source of Erel as it was, I added user and password and Gmail.com

The solution by @Enrique Gonzalez R will certainly work. But the question is for how long. Google is really pushing towards oauth (With a good reason).
Here is an excellent tutorial by Erel: https://www.b4x.com/android/forum/threads/b4x-sending-emails-with-gmail-rest-api.81736/