Did you turn on the "Allow less secure apps" on? go to this link
https://myaccount.google.com/security#connectedapps
Take a look at the Sign-in & security -> Apps with account access menu.
You must turn the option "Allow less secure apps" ON.
If is still doesn't work try one of these:
Go to https://accounts.google.com/UnlockCaptcha , and click continue and unlock your account for access through other media/sites.
Use double quote in your password: "your password"
And change your .env file
MAIL_DRIVER=smtp
MAIL_HOST=smtp.gmail.com
MAIL_PORT=587
[email protected]
MAIL_PASSWORD=xxxxxx
MAIL_ENCRYPTION=tls
because the one's you have specified in the mail.php will only be used if the value is not available in the .env file.