SMTP login error

Question

I am .NET developer, I am using Mail.dll for downloading mails and sending mails.
When I am trying to login with SMTP to send mails, I am getting below error:

"Limilabs.Client.ServerException:
5.7.14 Please log in via your web browser and then try again.
5.7.14 Learn more at
5.7.14 https://support.google.com/mail/bin/answer.py?answer=78754
z8sm24515758igl.20 - gsmtp

at Limilabs.Client.SMTP.Smtp.SendCommand(String command, Boolean throwException)
at Limilabs.Client.SMTP.Smtp.LoginPLAIN(String user, String adminUser, String adminPassword)
at Limilabs.Client.SMTP.Smtp.UseBestLogin(String user, String password)
at SetupEmail.Sendamil()"

Please help me.

Answer 1

The error returned by the SMTP server is clear:
"Please log in via your web browser and then try again. "

In most cases signing in from the web should resolve the issue.

First log in to the specified account via the web browser, you might have received an email with the blocked attempt information. Review it - you might need to confirm it was you.

There are several ways of dealing with this error:

• Enable "Access for less secure apps" at: https://www.google.com/settings/security/lesssecureapps
  (use incognito mode so you are sure you are logged in to correct account)

Please note that contrary to what the label says those applications (such as Thunderbird, Outlook and Mail.dll) are secure – they use TLS or SSL to secure the communication. The label name Gmail uses is misleading and false.

• Use OAuth 2.0 (OAuth 2.0 for installed applications, OAuth 2.0 for web applications, OAuth 2.0 for service accounts)

• Use application specific passwords (You can find how to create one in the Gmail support site)

• In some cases you'll need to use unlock captcha (use incognito mode so you are sure you are logged in to correct account): https://accounts.google.com/DisplayUnlockCaptcha