@순성 박 , Thanks for posting this question.
Apologies you’re experiencing this issue and for delayed response from over the weekend.
To narrow down the issue (if you haven't tried this already):
1.You may try to scale up to a higher ASP tier and then check (as a quick step)
2. If the Always On setting is off, please enable it from Azure Portal – Your WebApp > Configuration blade (> General settings).
To fetch more details about the issue, you may try these:
3. You may leverage App Service diagnostics from Azure Portal> Navigate to your App Service app in the Azure Portal. (screenshot below).
In the left navigation, click on Diagnose and solve problems - Review -
“Configuration and Management and “Availability and Performance” options.
4. Navigate through Kudu site on: https://<sitename>.scm.azurewebsites.net/api/logs/ , to fetch info.
5.Ensure that you have added SCM_DO_BUILD_DURING_DEPLOYMENT to your application settings and set to true. This setting ensures that the virtual environment in the App Service is correctly installing your dependencies. See for more info article.
Kindly let us know how it goes, I'll follow-up with you further.