The fist thing you should do is actually go and check the folders if
your war got unpacked inside the webapps folder. for that if your web
url is "xyz.azurewebsites.net" then try to open
xyz.scm.azurewebsites.net. This should redirect you to KUDU
interface where you can see few tabs. From those tabs select Debug
Console and then select CMD from the drop down. This should give you
a folder structure.Now Go to site->wwwroot->webapps . There check if
your war got unpacked.
If not then try restarting the web app and see id this does the
trick. If while creating your app service plan you have selected the
Standard pricing tier, change it to premium
Last but not the list you can enable logging for you app. Then go to
Monitoring-> Diagnostics logs . Turn those setting on. Then select
Log streaming(Just below Diagnostics logs).