If you have ever noticed that after a publish or restart of your Azure web app it might load slowly the first time, then when you refresh with F5 it is ok again.
If you've ever noticed this behavior an option might be to go inside of the Application Settings for the web app in the portal, and activating Always On, which keeps your web hydrated and responsive.
According to the information icon:
Indicates that your web app needs to be loaded at all times. By default, web apps are unloaded after they have been idle. It is recommended that you enable this option when you have continuous web jobs running on the web app.
Keep in mind that you will not be able to turn this feature on when using the Free version of Azure App Services. It is only available in Basic or Standard plans.
To recap, if your app runs continuous WebJobs or runs WebJobs triggered using a CRON expression, you should enable Always On, or the web jobs may not run reliably.