Well, for what it’s worth, I tried and also couldn’t get this to work. I stand by my supposition that it’s because Yahoo implemented SPA and Eudora doesn’t do that.

From: Joe Slaven [mailto:joeslaven@yahoo.com.au]
Sent: Wednesday, May 20, 2020 8:08 PM
To: Phil Smith III <phs3stuff@cox.net>; stunnel-users@stunnel.org
Subject: Re: [stunnel-users] Need help connecting Eudora to mail servers

I have pared down the config file to the bare essentials, dealing with Yahoo only, and still get the error message about username and password being not recognized. I have tested these via browser access to my Yahoo server, and found them to be correct.
Does anyone have any further suggestions please?

ERROR MESSAGE
"There has been an error transferring your mail.
POP Server [joeslaven@127.0.0.1] said ERR [AUTH] Username and password not accepted"
I used the same password to open My Account on Yahoo website without any problems


CONFIG FILE
debug=7
output = S:\stunnel-log.txt
;*******************************************************
;Yahoo connection
;*******************************************************
[yahoo-pop3]
client = yes
accept = 127.0.0.1:110
connect = pop.mail.yahoo.com:995
;verify = 2
;CAfile = ca-certs.pem
;checkHost = pop.mail.yahoo.com
;OCSPaia = yes

[yahoo-smtp]
client = yes
accept = 127.0.0.1:25
connect = smtp.mail.yahoo.com:465
;verify = 2
;CAfile = ca-certs.pem
;checkHost = smtp.mail.yahoo.com
;OCSPaia = yes


EUDORA SETTINGS
Checking Mail->Mail Server: 127.0.0.1
Sending Mail->SMTP Server: 127.0.0.1
Use submission port (587) is UNchecked
Secure Sockets when Sending or Receiving : Never
Default port settings :
SMPT Port (25)
POP Port (110)