Verify that the Ports are now 993 for Incoming and 465 for Outgoing.

For SSL for both Incoming and Outgoing, change the selections to SSL/TLS.

Verify that the Outgoing Server Hostname is.

Verify that the Incoming Server Hostname is.

Leave IMAP selected for Incoming Protocol – POP3 is an option but is not recommended.

Leave IMAP selected for Protocol (POP3 is an option but is not recommended) and click C onfigure manually.

Enter Your name, Email address and your email Password, then click C ontinue.

If you don’t see the menu bar across the top in the Windows version, click on the menu button (three horizontal stripes on the top right) and select View, T oolbar, M enu Bar.

Click F ile, N ew, E xisting Mail Account….

Gmail will not be such a pain and will stop deliberately blocking as it does not require 'less secure apps' option. Then a token is stored in the same place as the passwords and from then onwards Thunderbird will use that token to gain access to server. Then gmail would ask you to logon to confirm you really are you and say Thunderbird wants access.

If you have an IMAP account you could change the incoming 'Authentication Method:' to use 'OAuth' and also change the Outgoing SMTP Authentication Method to OAuth. It's a pain, but gmail will repeatedly do it on occasions.

Unfortunately gmail will deliberately block you every once in a while and you will need to go into gmail webmail account to enable the 'less secure apps' option again. This means gmail will require you to use that 'less secure apps' option. OR if you use an Imap account that uses 'Authentication Method: Normal Password' If you use a POP account it will use 'Authentication Method: Normal Password'

Mozilla thunderbird login failed