The OWA url (mail.imf.org) has been decommissioned and will no longer provide access to your IMF email via the web browser. With the recent move of email services to Office 365 cloud, you can access your email now through the new URL, http://portal.office.com.
This new Outlook Web App (http://portal.office.com) provides access to your email, calendar, task and Skype for Business from any PC. If you have any question or need assistance, support is available from the IT Help Desk 24hrs/day. (202) 623-6631 or (x36631).