Sending, receiving, and organizing email in Outlook.com
Have a look at:
https://support.microsoft.com/en-us/outlook/can-t-send-or-receive-email-in-outlook-com
Or try support on a computer via: https://outlook.live.com/
To get support in Outlook.com, tap or click here or select Help on the menu bar and enter your query. If the self-help doesn't solve your problem, scroll down to Still need help? and select Yes. If the above steps don't work or if you can't sign in, tap or click here.