Hi! I didn't see any replies to this so I just wanted to say-- I've been getting the same error with fetching updates from my gmail account. I believe it's due to the new requirement of 2 Factor Authorization stated below (so I'm searching for alternative mail servers that won't require connecting my personal cell number.) I'm also super new to all of this though and would be happy for any feedback or advice from people with more experience with email updates.
calibre, version 9.8.0 (gmail, macOS)
ERROR: Error Fetching Email: <p><b>An error has occurred while FanFicFare was fetching email.</b></p><p>If it was an authentication error, be aware:<ul><li>Microsoft mail servers such as
live.com,
outlook.com and
hotmail.com no longer allow third party apps like FanFicFare.</li><li>Gmail requires Two Factor Authentication and <a href='
https://support.google.com/accounts/answer/185833#app-passwords'>Google App Passwords</a>.</li><li>Usernames or passwords in personal.ini that contain the percent sign(%) must have it escaped as two percent signs(%%).</li></ul>
Traceback (most recent call last):
File "calibre_plugins.fanficfare_plugin.fff_plugin", line 625, in get_urls_from_imap_menu
url_list = get_urls_from_imap(prefs['imapserver'],
prefs['imapuser'],
imap_pass,
prefs['imapfolder'],
prefs['imapmarkread'],)
File "/Users/[ghoul]/Library/Preferences/calibre/plugins/FanFicFare.zip/fanficfare/geturls.py", line 197, in get_urls_from_imap
status = mail.login(user, passwd)
File "imaplib.py", line 709, in login
imaplib.IMAP4.error: b'[AUTHENTICATIONFAILED] Invalid credentials (Failure)'