You are listing two separate issues, (i) login problems with Outlook and (ii) login problems with webmail. You need to provide more information. About webmail, try
https://192.168.1.1/webmail - substitute your local IP address for the one I used in this example. Search the forums, there are quite a few posts on both topics. Check the bugtracker at bugzilla (links on the left), there are also a couple of recent entries about your topics, it may help.
If you still have a problem, please report it via the bug tracker, one problem per Bug. Use the button/links located on the left or go to
http://bugs.contribs.org/enter_bug.cgi - you may need to register. Please describe exactly what you have done and exactly what you see in response.