Getting error while sending email through Gmail SMTP - "Please log in via your web browser and then try again. 534-5.7.14" [closed]

Question

I know this is an older issue, but I recently had the same problem and was having issues resolving it, despite attempting the DisplayUnlockCaptcha fix. This is how I got it alive.

Head over to Account Security Settings (https://www.google.com/settings/security/lesssecureapps) and enable "Access for less secure apps", this allows you to use the google smtp for clients other than the official ones.

Update

Google has been so kind as to list all the potential problems and fixes for us. Although I recommend trying the less secure apps setting. Be sure you are applying these to the correct account.

• If you've turned on 2-Step Verification for your account, you might need to enter an App password instead of your regular password.
• Sign in to your account from the web version of Gmail at https://mail.google.com. Once you’re signed in, try signing in
  to the mail app again.
• Visit http://www.google.com/accounts/DisplayUnlockCaptcha and sign in with your Gmail username and password. If asked, enter the
  letters in the distorted picture.
• Your app might not support the latest security standards. Try changing a few settings to allow less secure apps access to your account.
• Make sure your mail app isn't set to check for new email too often. If your mail app checks for new messages more than once every 10
  minutes, the app’s access to your account could be blocked.

I did this every time the problem happens:

https://accounts.google.com/DisplayUnlockCaptcha

• problem sorted in my case!

I recently got this message, too, after I switched the data center location of a web application sending through Google SMTP.

The URL that apparently Google means is: https://support.google.com/mail/answer/78754. At that link, one of the steps is to reset your password. Not coincidentally, I also received an email from google with a subject of "Suspicious sign in prevented" that instructed me to change my password.

After resetting my password, I was back to using Google SMTP as usual.

I know this question is already been answered but for new comers those two solutions may help:

1. Make sure your gmail is allowing low secure apps to sign in, you can turn it on here: https://www.google.com/settings/security/lesssecureapps.
2. Change your password.