I have been having the above mentioned issue since the beginning of the year and not sure what to do anymore. My gmail email forwarder was working fine up and I am getting this everytime I am sending an email:
Google just blocked someone from signing into your Google account firstname.lastname@example.org from an app that may put your account at risk.
Less secure app
Wednesday, 14 February 2018 06:38 (New York Time)
Don’t recognise this activity?
If you didn’t recently receive an error while trying to access a Google service, like Gmail, from a non-Google application, someone may have your password.
SECURE YOUR ACCOUNT
Are you the one who tried signing in?
Google will continue to block sign-in attempts from the app that you’re using because it has known security problems or is out of date. You can continue to use this app by allowing access to less secure apps, but this may leave your account vulnerable.
Domain is vpyn.ga and all nameservers point to 000webhost.
Hope you can help.