Sent mail not confirming as sent in Oultook / Live Mail – Windows 10 – Edge Browser

I recently was upgraded to Windows 10 (Unintentionally, I might add!). My browser was also upgraded to the "Edge" browser. Since then I am experiencing a problem with my sent e-mails (specifically when there is an attachment). I use Outlook.com/window live mail (prior it was Hotmail). When I send an -mail with an attachment I hit send and nothing happens. There is no change in the screen to reflect that the mail was sent. There is no longer a send button showing, though. when I attempt to close that window I get a warning message that anything I typed will be lost and the message was not sent. If I then go to my sent folder the message does appear as having been sent with the attachments. I have contacted the receivers just to confirm and they did receive my e-mail. Each time this occurs I copy the body of the outgoing message just in case I do lose it but it is always in the sent folder where it should be. How to I get back to the normal occurrence that shows that I have sent me mail after hitting sent?