My emails not working

I am trying to get my emails working but cannot.
I have several sites but none of these are recieving or sending emails

When I send an email to any of the sites there is a message
Password required for SMTP

  • Server says
    Authentication credentials invalid.
    Username j—
    Password *******

I suddenly had some messages from Google requiring me to authorise emClient to receive information which I did.

After the Google updates I am still getting the same message.

Can you please explain and what I should do to correct this error?
Many thanks

I can receive mail on another separate PC

Thank you

John H