A problem with syncing from local to imap

[Marcin Borkowski]

Hello,

I installed offlineimap (version 6.3.4), configured it by modifying the
example conf file as little as possible;), and tried to use it.  It
downloads the messages from the remote server properly, but somehow
does not do the reverse (i.e., does not copy new emails from my local
repository to the remote one).  After enabling debug, it complains
about read-only remote repository (but I have readonly = False in
my ~/.offlineimaprc).  I downloaded the newest (6.5.4) version, and the
error message disappears, but the messages still don't get copied. (I
need this behavior since I want to use a mail client which just copies
sent messages to the "Sent" folder in my local maildir, and I want to
have them copied to the remote server, too, in case I want to access my
emails e.g. via web client.)  What may be the reason for this? Here is
the relevant portion of my ~/.offlineimaprc:

[general]
metadata = ~/.offlineimap
accounts = Main, Wmi, Mborkpl
maxsyncaccounts = 3
ui = Blinkenlights
ignore-readonly = no
socktimeout = 60

[mbnames]
enabled = no
filename = ~/Mutt/muttrc.mailboxes
header = "mailboxes "
peritem = "+%(accountname)s/%(foldername)s"
sep = " "
footer = "\n"

[ui.Curses.Blinkenlights]
statuschar = .

[Account Wmi]
localrepository = LocalWmi
remoterepository = RemoteWmi
maxage = 365

[Repository LocalWmi]
type = Maildir
localfolders = ~/Maildir/wmi
sep = /
restoreatime = no

[Repository RemoteWmi]
type = IMAP
remotehost = imap.wmi.amu.edu.pl
ssl = yes
remoteuser = mbork
remotepassfile = ***
maxconnections = 2
holdconnectionopen = no
subscribedonly = no
readonly = False
cert_fingerprint = ***

Best,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Adam Mickiewicz University