IIS is not serving my static file on Azure

I have a static file, letsencrypt.txt, in the wwwroot folder on my website.
But going to http://{domain}.com/letsencrypt.txt gives 404.

This is not on a virtual machine, shared or otherwise. I do not have root access or CPanel access. I do not have any extra Azure Storage.

I do have a Subscription, a Resource Group, an App Service, an App Service Plan, and an API Management Service. I do have FTP access, so I can see the file structure and upload files and download log files.

In practice, all I really know is that the file is at /site/wwwroot.

The log shows

<tr class="alt"><th>Requested URL</th><td>https://{domain}:80/letsencrypt.txt</td></tr> 
<tr><th>Physical Path</th><td>**C:\home\site\wwwroot\letsencrypt.txt**</td></tr> 

which is exactly where I think the file is located.
I can't see any reason for it to not be able to find the file.
Nothing in the log about access control or permissions.

I thought that perhaps the https issue was a result of the DNS redirect, but I get the same 404 if I go directly to {domain}.azurewebsites.net. And it still redirects to https.

One interesting point is that, here in the log, it specifies port 80 even though it says https.

Here is the entire web.config.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <location path="." inheritInChildApplications="false">
    <system.webServer>
      <handlers>
        <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" />
      </handlers>
      <aspNetCore processPath="dotnet" arguments=".\SmartTagsAPI.dll" stdoutLogEnabled="false" stdoutLogFile="\\?\%home%\LogFiles\stdout" hostingModel="inprocess" />
      <rewrite> 
        <rules> 
<!--           <rule name="wildcard"> 
            <match url=".*well-known/acme-challenge/(?!.*?\.txt$)(.*)$" /> 
            <action type="Redirect" url="LetsEncrypt/letsencrypt.txt" /> 
          </rule>  -->
        </rules> 
      </rewrite> 
    </system.webServer>
  </location>
</configuration>