When your application tries to send an email using a Gmail account you may get the error message:
Unable to read data from the transport connection: net_io_connectionclosed.
One of the causes can be, when “Less secure apps” are not allowed to use the Gmail account.
To enable “Less secure apps” to use the Gmail account
- Log into Gmail and navigate to
https://www.google.com/settings/security/lesssecureapps - Select the Turn on radio button