I have re-installed PMail v. 4.8 and starting over. I cannot send because a 530 Authentication is required. Explain to me what this is and how to do it or fix it. I am able to connect to GMail and receive but not send.

An authentication error means that the user name or password is incorrect so I would start by going to the SMTP host configuration and re-entering the user name and password making sure there are no errant spaces.

I suggest specifying the user name and password rather that using the option to login using the POP3 credentials.

I should have asked this prior to my previous post...

In Google, have you enabled 2 factor authentication and created an app password for Pegasus Mail? If not, you need to do that. An alternative is to upgrade to the Pegasus Mail v4.81 beta and use its Gmail OAUTH2 feature.

For some unknown reason my original PMail program that was locked up has recovered and is now working for me as before. But thank you anyway, Brian.