Hi, I wasn't able to receive or send mail via smtp/TLS since Feb 08 2021, so I found out about OAuth and followed the instruction here [https://support.mozilla.org/en-US/kb/thunderbird-and-yahoo#w_important-changes-to-authentication-method-notice Mozilla Link paragraph 'Important Changes'] I understood the help instruction the way that TB gets a kind of cookie/key to sign in automatically to Yahoo each time, 'in the background', as to work quite as one is used to? But I keep getting a Yahoo pop-up window, asking me to sign in to my Yahoo mail account each time (user name, pass word). Is that supposed to happen? I've re-checked. Everything looks as if I followed the instruction (cookies accepted, OAuth in both setting, server names and ports correct). Any ideas?