MS Office365 'IMAP' server

Richard Lewis richard.lewis at
Thu Feb 19 11:33:33 GMT 2015

Hi there,

My organisation sold out to Microsoft for email and calendar services
a year or so ago, making us all switch to Office365.

I've been finding that I have problems connecting to the IMAP server
it provides. It often takes several attempts to get a client to
authenticate. Once it has authenticated, it will then normally stay
connected for the rest of the day, although sometimes if left
"unattended" (I'm not sure exactly what happens) it will drop the
connection and I have to do the whole connection dance again. One odd
feature is that the problem only seems to occur when I'm connected to
my organisation's ethernet network; if I use their wifi (which is not
simply a router stuck on the same network, it's a completely different
network), or when I'm connected via any other ISP the problem doesn't

I switched to offlineimap a few months ago because I was getting
frustrated with having to wait for my mail client to connect to this
server. At least offlineimap is just in the background and I can still
work with the Maildir even while it's busy failing to
authenticate. Although it is still slightly annoying that it eventally
gives up and the process dies, and then I have to start it again.

However, I really would like to find a solution to this problem. I've
tried asking my organisation's IT services department but they tend to
ignore my tickets, I guess because they have no idea. I found some
mention of throttling in the MS server
<> which
could be relevant.

Does anyone have any suggestions how I could go about investigating
this? Are there any settings in offlineimap that might give me more
information about what's going on?


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