As MS stays 100% quiet about this issue, let me help you uncover it !
Can you go to your WEBMAIL outlook account please ? Go to hotmail.com and log in to your account.
Then go to options>pop&imap
First enable POP if you haven't yet.
Then secondly, have a look at the set protocols :
in the option pop&imap you can see the protocols used for incoming mail and outgoing mail.
Incoming should be "SSL"...but I suspect you have it set to "TLS"
Outgoing (smtp) should be "TLS", but you probably have it set at "STARTTLS".
This is MICROSOFT's doing, NOT YOURS !
MS is migrating (it seems) those protocols globally, from SSL to TLS for incoming mail, and from TLS to STARTTLS for outgoing mail.
I have already mentioned this to MS support, and all they can respond is that I have a 'misbehaving' account. Which is total BS by the way. All my accounts are verified.
So for everyone having sync issues, and I mean EVERYONE globally having issues syncing outlook on either MS Outlook app, Android or Iphone, Ipad,... anything other than the webmail itself, is in fact affected by this change in mail protocols !
If you have sync issues, check the pop&imap option, if you have TLS and STARTTLS instead of SSL and TLS, then you should blame MS, because it is a GLOBAL issue coming from THEIR SERVER END !
Hope THIS will help a LOT of users out there THINKING it is something they can fix. The END-USER CANNOT FIX THIS !!!
MS should first pull their finger and admit this issue, then start to fix it.
So support, pls STOP giving us the run-around. The issue is SERVER-END, and has to do with the protocol change in MANY BUT NOT ALL hotmail accounts.