Did you configure the email account in the online account? What email client do you use? The online accounts are supposed to handle plain, are you sure you issue is not that you need a security option instead of plain (like it's described in https://gitlab.gnome.org/GNOME/gnome-online-accounts/issues/27)
** Package changed: gnome-control-center (Ubuntu) => gnome-online- accounts (Ubuntu) -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-control-center in Ubuntu. https://bugs.launchpad.net/bugs/1799259 Title: Online Accounts imap does not support plain Status in gnome-online-accounts package in Ubuntu: Incomplete Bug description: When I try to log in with IMAP It does not go and alerts that it does not support plain. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: gnome-control-center 1:3.28.2-0ubuntu0.18.04.2 ProcVersionSignature: Ubuntu 4.15.0-38.41-generic 4.15.18 Uname: Linux 4.15.0-38-generic x86_64 ApportVersion: 2.20.9-0ubuntu7.4 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Mon Oct 22 09:21:51 2018 ExecutablePath: /usr/bin/gnome-control-center InstallationDate: Installed on 2018-10-18 (4 days ago) InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725) ProcEnviron: XDG_RUNTIME_DIR=<set> SHELL=/bin/bash PATH=(custom, no user) LANG=en_US.UTF-8 SourcePackage: gnome-control-center UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-online-accounts/+bug/1799259/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp