Configure Gmail In Thunderbird

1. Create Email Account in GMail
2. Go to Setting -> Forwarding and POP/IMAP
3. In POP Download Kindly Select : POP is enabled for all emails
4. Go to : Less Secure Apps and Allow Less Secure Apps : ON
5. Go to : Display Unlock Captcha and Allow : Press Continue Button
6. Download Thunderbird
7. Go to File -> New -> Existing Email Account
8. Fill The Details Your Name, Email Address, Password
9. Press Continue Button
10. Go to Manual Config
11. Use Details Give Below
    1. Incoming
       1. Incoming : POP3
       2. Server Hostname : pop.gmail.com
       3. Port : 995
       4. Connection Security : SSL/TLS
       5. Authentication : Normal Password
       6. Username : Your Gmail Username
    2. Outgoing
       1. Outgoing : SMTP
       2. Server Hostname : smtp.gmail.com
       3. Port : 465
       4. Connection Security : SSL/TLS
       5. Authentication : OAuth2
       6. Username : Your Gmail Username
12. Press Test Button
13. After That Press Done Button
14. Test SMTP Configuration Via Sending Test Mails From Configured Account to Another Account
15. Test POP Configuration Via Sending Test Mails From Another Account to Configured Account.

Note : If Meanwhile Thunderbird Asking for Web Based Login Then Kindly Process For That also.